id: P69805
gene_symbol: manZ
product_type: PROTEIN
status: IN_PROGRESS
taxon:
  id: NCBITaxon:83333
  label: Escherichia coli (strain K12)
description: >-
  ManZ is the EIID component of the mannose-specific phosphoenolpyruvate-dependent sugar
  phosphotransferase system (Man-PTS) in E. coli K12. It is an integral inner membrane protein
  with multiple transmembrane helices that, together with ManY (EIIC), forms the transmembrane
  translocation channel of the mannose permease. The ManY/ManZ heterodimer assembles as a
  homotrimer of protomers (PMID:31209249). ManZ contains part of the substrate-binding site.
  The ManXYZ complex transports mannose, glucose, fructose, and N-acetylglucosamine via
  PEP-dependent phosphorylation (PMID:2951378, PMID:2999119). The Man-PTS also serves as a
  receptor for bacteriophage lambda DNA injection (PMID:353494, PMID:2951378) and as a
  chemoreceptor for sugars (PMID:4604906). ManZ (II-MMan) together with ManY (II-PMan) alone
  are sufficient for penetration of lambda DNA, while all three subunits (ManX, ManY, ManZ)
  are required for sugar transport and phosphorylation (PMID:2951378).

existing_annotations:
# --- plasma membrane (IBA) ---
- term:
    id: GO:0005886
    label: plasma membrane
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: >-
      ManZ is an integral inner membrane protein of E. coli, experimentally demonstrated by
      topology analysis (PMID:15919996, PMID:8774730), membrane proteomics (PMID:17309111),
      and cryo-EM structure (PMID:31209249). The IBA annotation from phylogenetic inference
      is fully consistent with the experimental data.
    action: ACCEPT
    reason: >-
      Plasma membrane (inner membrane in E. coli) localization is a core aspect of ManZ
      function. This is supported by extensive experimental evidence from topology studies
      and structural determination. The IBA annotation is appropriate.
    supported_by:
    - reference_id: PMID:2999119
      supporting_text: >-
        IIMan, a 27-kDa protein, is the transmembrane component of the complex.
    - reference_id: PMID:15919996
      supporting_text: >-
        we established the periplasmic or cytoplasmic locations of the C termini for 601 inner membrane proteins
    - reference_id: file:ECOLI/manZ/manZ-deep-research-falcon.md
      supporting_text: |-
        ManZ is an **inner (cytoplasmic) membrane** protein in the ManXYZ complex.

# --- PTS system (IBA) ---
- term:
    id: GO:0009401
    label: phosphoenolpyruvate-dependent sugar phosphotransferase system
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: >-
      ManZ is the EIID component of the mannose PTS. The IBA annotation from phylogenetic
      inference is consistent with experimental demonstration that ManZ is part of the
      mannose permease of the PEP-dependent PTS (PMID:2951378, PMID:2999119).
    action: ACCEPT
    reason: >-
      Involvement in the PEP-dependent sugar PTS is the core biological process for ManZ.
      This is supported by direct experimental evidence from multiple publications.
    supported_by:
    - reference_id: PMID:2951378
      supporting_text: >-
        The mannose permease of the bacterial phosphotransferase system mediates sugar
        transport across the cytoplasmic membrane concomitant with sugar phosphorylation.
    - reference_id: PMID:2999119
      supporting_text: >-
        The mannose-permease complex of the phosphoenolpyruvate-dependent phosphotranferase
        system exhibits two apparently unrelated activities.
    - reference_id: file:ECOLI/manZ/manZ-deep-research-falcon.md
      supporting_text: |-
        ManZ is the **EIID** subunit that partners with ManY (EIIC) to form the membrane translocation module. Foundational work describes the PTS chemical steps (phosphate transfer through ManX domains to the sugar at the membrane-embedded IIC module), while positioning ManZ as a critical membrane component that is not a classic phosphoryl-transfer domain but is required for transport and forms part of the **pore/translocation** apparatus.

# --- plasma membrane (IEA) ---
- term:
    id: GO:0005886
    label: plasma membrane
  evidence_type: IEA
  original_reference_id: GO_REF:0000044
  review:
    summary: >-
      IEA annotation based on UniProt subcellular location mapping. Duplicates the
      experimentally supported and IBA annotations for the same term.
    action: ACCEPT
    reason: >-
      This IEA annotation is redundant with the IBA and multiple IDA annotations for
      GO:0005886, but it is not incorrect. Plasma membrane localization is well established.

# --- PTS system (IEA from InterPro) ---
- term:
    id: GO:0009401
    label: phosphoenolpyruvate-dependent sugar phosphotransferase system
  evidence_type: IEA
  original_reference_id: GO_REF:0000002
  review:
    summary: >-
      IEA annotation inferred from InterPro domain IPR004704 (PTS_IID_man). Duplicates
      the IBA and IDA annotations for the same term.
    action: ACCEPT
    reason: >-
      This IEA annotation from InterPro domain mapping is redundant with experimental
      annotations but is not incorrect. The InterPro domain PTS_IID_man correctly maps
      to PTS involvement.

# --- membrane (IEA from InterPro) ---
- term:
    id: GO:0016020
    label: membrane
  evidence_type: IEA
  original_reference_id: GO_REF:0000002
  review:
    summary: >-
      IEA annotation from InterPro mapping. GO:0016020 (membrane) is a parent of
      GO:0005886 (plasma membrane), which is already annotated with experimental evidence.
    action: ACCEPT
    reason: >-
      While this is less specific than the plasma membrane annotation, it is not incorrect.
      IEA annotations at broader levels are acceptable when more specific experimental
      annotations also exist.

# --- PTS system (IDA, PMID:2951378) ---
- term:
    id: GO:0009401
    label: phosphoenolpyruvate-dependent sugar phosphotransferase system
  evidence_type: IDA
  original_reference_id: PMID:2951378
  review:
    summary: >-
      Erni et al. 1987 determined the complete amino acid sequence of the mannose permease
      subunits and demonstrated that all three subunits (IIIMan/ManX, II-PMan/ManY,
      II-MMan/ManZ) are required for sugar transport and phosphorylation via the PTS
      (PMID:2951378). This is direct experimental evidence for ManZ involvement in the PTS.
    action: ACCEPT
    reason: >-
      Strong direct experimental evidence from the foundational study characterizing the
      mannose permease components.
    supported_by:
    - reference_id: PMID:2951378
      supporting_text: >-
        The mannose permease of the bacterial phosphotransferase system mediates sugar
        transport across the cytoplasmic membrane concomitant with sugar phosphorylation.
        ...All three subunits are required for sugar transport and phosphorylation

# --- mannose transmembrane transport (NAS, PMID:2951378) ---
- term:
    id: GO:0015761
    label: mannose transmembrane transport
  evidence_type: NAS
  original_reference_id: PMID:2951378
  review:
    summary: >-
      NAS annotation based on PMID:2951378, which describes the mannose permease and its
      role in mannose transport. The abstract states the permease "mediates sugar transport
      across the cytoplasmic membrane" and the system is named the mannose permease.
    action: ACCEPT
    reason: >-
      Mannose transmembrane transport is a core function of the ManXYZ complex, of which
      ManZ is the EIID subunit. While the NAS evidence code is weaker, the annotation is
      well supported by the literature.
    supported_by:
    - reference_id: PMID:2951378
      supporting_text: >-
        The mannose permease of the bacterial phosphotransferase system mediates sugar
        transport across the cytoplasmic membrane concomitant with sugar phosphorylation.
    - reference_id: PMID:2999119
      supporting_text: >-
        It mediates active transport concomitant with phosphorylation of mannose,
        2-deoxyglucose, and a number of other hexoses
    - reference_id: file:ECOLI/manZ/manZ-deep-research-falcon.md
      supporting_text: |-
        It transports mannose as its principal substrate, but multiple sources emphasize it can also transport and/or phosphorylate additional hexoses and amino-sugars.

# --- mannose transmembrane transport (IDA, PMID:5545083) ---
- term:
    id: GO:0015761
    label: mannose transmembrane transport
  evidence_type: IDA
  original_reference_id: PMID:5545083
  review:
    summary: >-
      Kundig and Roseman 1971 characterized constitutive membrane-bound enzymes II of the
      E. coli PTS, including characterization of mannose transport. Only the abstract is
      available for this early publication.
    action: ACCEPT
    reason: >-
      Mannose transport is a core function of the Man-PTS. This early characterization
      study provided foundational evidence. The qualifier in GOA is "acts_upstream_of_or_within"
      which is appropriate for the older literature where the specific gene product contribution
      was less precisely defined.
    supported_by:
    - reference_id: PMID:5545083
      supporting_text: >-
        Sugar transport. II. Characterization of constitutive membrane-bound enzymes
        II of the Escherichia coli phosphotransferase system.

# --- N-acetylglucosamine transport (EXP, PMID:6252281) ---
- term:
    id: GO:0015764
    label: N-acetylglucosamine transport
  evidence_type: EXP
  original_reference_id: PMID:6252281
  review:
    summary: >-
      Jones-Mortimer and Kornberg 1980 demonstrated that N-acetylglucosamine enters E. coli
      by two distinct PTS systems, one of which is the PtsM (manZ) system (PMID:6252281).
      This is a secondary transport substrate of the mannose PTS.
    action: KEEP_AS_NON_CORE
    reason: >-
      N-acetylglucosamine transport is a genuine but non-core function of the Man-PTS.
      The primary substrates are mannose and glucose. The ptsM system is one of two PTS
      systems that can transport N-acetylglucosamine.
    supported_by:
    - reference_id: PMID:6252281
      supporting_text: >-
        N-Acetylglucosamine enters E. coli by two distinct phosphotransferase systems
        ...One of these is the PtsM system
    - reference_id: file:ECOLI/manZ/manZ-deep-research-falcon.md
      supporting_text: |-
        EcoSal Plus summarizes that ManXYZ transports **mannose** and is “relatively promiscuous,” transporting **glucose**, **2-deoxyglucose**, **N-acetylglucosamine**, **N-acetylmannosamine**, and **galactosamine**.

# --- D-glucose import across plasma membrane (IDA, PMID:5545083) ---
- term:
    id: GO:0098708
    label: D-glucose import across plasma membrane
  evidence_type: IDA
  original_reference_id: PMID:5545083
  review:
    summary: >-
      Kundig and Roseman 1971 characterized membrane-bound enzymes II of the PTS. The
      mannose PTS is known to transport glucose (as 2-deoxyglucose) in addition to mannose
      (PMID:2999119). Glucose import is a secondary but well-established substrate of
      the Man-PTS.
    action: KEEP_AS_NON_CORE
    reason: >-
      Glucose transport via the Man-PTS is well established but is not the primary evolved
      function of the mannose permease. E. coli has a dedicated glucose PTS (PtsG). The
      Man-PTS can transport glucose but it is a secondary substrate.
    supported_by:
    - reference_id: PMID:2999119
      supporting_text: >-
        It mediates active transport concomitant with phosphorylation of mannose,
        2-deoxyglucose, and a number of other hexoses

# --- fructose import across plasma membrane (EXP, PMID:4153999) ---
- term:
    id: GO:1990539
    label: fructose import across plasma membrane
  evidence_type: EXP
  original_reference_id: PMID:4153999
  review:
    summary: >-
      Ferenci and Kornberg 1974 studied the role of PTS-mediated fructose phosphorylation
      in E. coli growth on fructose. The mannose PTS can transport fructose, but fructose
      is a secondary substrate and E. coli has a dedicated fructose PTS. Note: the primary
      citation (PMID:4153999) is only partially cached (title/metadata only; no full text
      or abstract body), so the substrate confirmation supporting this annotation is drawn
      from secondary sources (the falcon deep research quoting later functional/regulatory
      studies). The companion genetic study PMID:4154035 provides independent support for
      mannose-PTS involvement in fructose utilization.
    action: KEEP_AS_NON_CORE
    reason: >-
      Fructose import is a genuine but non-core function of the Man-PTS. E. coli has a
      dedicated fructose-specific PTS. The Man-PTS can phosphorylate fructose to fructose
      6-phosphate as a secondary activity.
    supported_by:
    - reference_id: file:ECOLI/manZ/manZ-deep-research-falcon.md
      supporting_text: |-
        A detailed regulatory/functional study likewise states manXYZ can transport many sugars, including **glucose**, **mannose**, and the amino sugars **glucosamine** and **N-acetylglucosamine**, and also reports transport of **2-deoxyglucose**, **fructose**, and more.

# --- fructose import across plasma membrane (EXP, PMID:4154035) ---
- term:
    id: GO:1990539
    label: fructose import across plasma membrane
  evidence_type: EXP
  original_reference_id: PMID:4154035
  review:
    summary: >-
      Jones-Mortimer and Kornberg 1974 performed genetical analysis of fructose utilization
      in E. coli. This provides genetic evidence for the involvement of the mannose PTS
      in fructose uptake as a secondary activity.
    action: KEEP_AS_NON_CORE
    reason: >-
      Duplicate annotation for fructose import with a different reference. Fructose transport
      is a genuine secondary function of the Man-PTS, not a core function.

# --- plasma membrane (IDA, PMID:15919996) ---
- term:
    id: GO:0005886
    label: plasma membrane
  evidence_type: IDA
  original_reference_id: PMID:15919996
  review:
    summary: >-
      Daley et al. 2005 performed global topology analysis of the E. coli inner membrane
      proteome using C-terminal GFP/PhoA fusions, establishing the topology and inner
      membrane localization of 601 proteins including ManZ (PMID:15919996).
    action: ACCEPT
    reason: >-
      Direct experimental evidence for inner membrane (plasma membrane) localization from
      a large-scale topology study. This is strong IDA evidence.
    supported_by:
    - reference_id: PMID:15919996
      supporting_text: >-
        we established the periplasmic or cytoplasmic locations of the C termini for 601 inner membrane proteins

# --- plasma membrane (IDA, PMID:17309111) ---
- term:
    id: GO:0005886
    label: plasma membrane
  evidence_type: IDA
  original_reference_id: PMID:17309111
  review:
    summary: >-
      Zhang et al. 2007 identified ManZ as an integral membrane protein in the inner
      membrane fraction of E. coli by 2-D LC-MS/MS membrane proteome analysis (PMID:17309111).
    action: ACCEPT
    reason: >-
      Direct identification of ManZ in the inner membrane proteome fraction. While this is
      a proteomic detection study rather than a targeted experiment, it provides valid IDA
      evidence for membrane localization.
    supported_by:
    - reference_id: PMID:17309111
      supporting_text: >-
        Both organic solvent and surfactant have been used for dissolving membrane
        proteins for shotgun proteomics.
        ...to dissolve and analyze the inner membrane fraction of an Escherichia coli K12 cell lysate

# --- plasma membrane (IDA, PMID:2999119) ---
- term:
    id: GO:0005886
    label: plasma membrane
  evidence_type: IDA
  original_reference_id: PMID:2999119
  review:
    summary: >-
      Erni and Zanolari 1985 purified the IIMan/IIIMan complex and demonstrated that IIMan
      (ManZ) is the transmembrane component (PMID:2999119).
    action: ACCEPT
    reason: >-
      Foundational experimental evidence from the original characterization study that
      ManZ is a transmembrane component localized to the cytoplasmic membrane.
    supported_by:
    - reference_id: PMID:2999119
      supporting_text: >-
        IIMan, a 27-kDa protein, is the transmembrane component of the complex.

# --- PTS system (IDA, PMID:2999119) ---
- term:
    id: GO:0009401
    label: phosphoenolpyruvate-dependent sugar phosphotransferase system
  evidence_type: IDA
  original_reference_id: PMID:2999119
  review:
    summary: >-
      Erni and Zanolari 1985 cloned the genes and purified the mannose permease complex,
      demonstrating its function in the PEP-dependent PTS (PMID:2999119).
    action: ACCEPT
    reason: >-
      Direct experimental evidence from gene cloning and protein purification study
      demonstrating ManZ role in the PEP-dependent PTS.
    supported_by:
    - reference_id: PMID:2999119
      supporting_text: >-
        The mannose-permease complex of the phosphoenolpyruvate-dependent phosphotranferase
        system exhibits two apparently unrelated activities. It mediates active transport
        concomitant with phosphorylation of mannose, 2-deoxyglucose, and a number of other hexoses

# --- mannose PTS transporter activity (IDA, PMID:2999119) ---
- term:
    id: GO:0022870
    label: protein-N(PI)-phosphohistidine-mannose phosphotransferase system transporter
      activity
  evidence_type: IDA
  original_reference_id: PMID:2999119
  review:
    summary: >-
      GO:0022870 describes the mannose PTS transporter activity, defined as catalysis of
      PEP-dependent phosphoryl transfer-driven transport of mannose across a membrane.
      Erni and Zanolari 1985 demonstrated that the purified IIMan/IIIMan complex mediates
      PEP-dependent mannose transport and phosphorylation (PMID:2999119). Both IIMan and
      IIIMan are required for phosphorylation of 2-deoxyglucose in vitro.
    action: ACCEPT
    reason: >-
      This is the most specific and informative molecular function annotation for ManZ.
      It correctly captures the mannose PTS transporter activity as the core molecular
      function. Note that this activity is a property of the ManXYZ complex rather than
      ManZ alone, but ManZ (EIID) is an essential component of the translocation channel.
    supported_by:
    - reference_id: PMID:2999119
      supporting_text: >-
        It mediates active transport concomitant with phosphorylation of mannose,
        2-deoxyglucose, and a number of other hexoses
        ...IIMan and IIIMan are both required for phosphorylation of 2-deoxyglucose in vitro

# --- membrane (HDA, PMID:16858726) ---
- term:
    id: GO:0016020
    label: membrane
  evidence_type: HDA
  original_reference_id: PMID:16858726
  review:
    summary: >-
      Lasserre et al. 2006 identified ManZ as part of membrane protein complexes in E. coli
      using 2-D BN/SDS-PAGE complexomics (PMID:16858726). GO:0016020 (membrane) is less
      specific than GO:0005886 (plasma membrane).
    action: ACCEPT
    reason: >-
      This is a valid HDA annotation from a complexomics study. While less specific than
      the plasma membrane annotations, it is not incorrect and provides independent
      high-throughput evidence for membrane association.
    supported_by:
    - reference_id: PMID:16858726
      supporting_text: >-
        the cytosolic and membrane protein complexes of Escherichia coli were separated.
        Then, the different partners of each protein complex were identified by LC-MS/MS.

# --- NEW: transmembrane transporter complex ---
- term:
    id: GO:1902495
    label: transmembrane transporter complex
  evidence_type: IPI
  original_reference_id: PMID:31209249
  review:
    summary: >-
      The UniProt record lists GO:1902495 (transmembrane transporter complex) with IPI
      evidence from ComplexPortal, but this annotation is absent from the GOA file. The
      cryo-EM structure (PMID:31209249) shows ManZ forms a homotrimer of ManY/ManZ
      heterodimers, constituting a transmembrane transporter complex.
    action: NEW
    reason: >-
      ManZ is part of the ManYZ transmembrane transporter complex (CPX-5968 in ComplexPortal).
      The cryo-EM structure definitively demonstrates this complex architecture. This is
      a core cellular component annotation that should be present.
    supported_by:
    - reference_id: PMID:31209249
      supporting_text: >-
        we have solved the cryo-EM structure of ManYZ at the inward-facing
        conformational state. Man-PTS transporters use an elevator mechanism for
        substrate transportation, in which the substrate-binding Core domain can
        undergo a rigid-body rotation across the cell membrane.
    - reference_id: PMID:31209249
      supporting_text: >-
        Cartoon representation of the ManYZ structure is shown in two perpendicular
        views. ... VmotifY and VmotifZ interlocked to form Vmotif domain, whereas
        CoreY and CoreZ give rise to Core domain.

references:
- id: file:ECOLI/manZ/manZ-deep-research-falcon.md
  title: >-
    Falcon (Edison Scientific) deep research report on E. coli manZ (PTS system
    mannose-specific EIID component, UniProt P69805)
  findings:
  - statement: >-
      ManZ (EIID-Man) partners with ManY (EIIC) to form the inner-membrane
      translocation module of the mannose PTS; it is not a phosphoryl-transfer
      domain but is required for transport and forms part of the pore/translocation
      apparatus.
    supporting_text: |-
      ManZ is the **EIID** subunit that partners with ManY (EIIC) to form the membrane translocation module. Foundational work describes the PTS chemical steps (phosphate transfer through ManX domains to the sugar at the membrane-embedded IIC module), while positioning ManZ as a critical membrane component that is not a classic phosphoryl-transfer domain but is required for transport and forms part of the **pore/translocation** apparatus.
    reference_section_type: OTHER
  - statement: >-
      ManZ is an inner (cytoplasmic) membrane protein of the ManXYZ complex.
    supporting_text: |-
      ManZ is an **inner (cytoplasmic) membrane** protein in the ManXYZ complex.
    reference_section_type: OTHER
  - statement: >-
      The ManXYZ (EIIMan) system is a broad-specificity PTS transporter whose
      primary biological output is inner-membrane import of mannose-family
      substrates coupled to phosphorylation.
    supporting_text: |-
      Together, these sources support that ManZ’s primary biological role is as part of a **PTS permease complex** whose functional output is **inner-membrane import of mannose-family substrates coupled to phosphorylation**, supporting growth on these sugars and contributing to global carbon uptake under varying conditions.
    reference_section_type: OTHER
  - statement: >-
      ManXYZ transports mannose as principal substrate and is relatively
      promiscuous, also transporting glucose, 2-deoxyglucose, N-acetylglucosamine,
      N-acetylmannosamine, and galactosamine.
    supporting_text: |-
      EcoSal Plus summarizes that ManXYZ transports **mannose** and is “relatively promiscuous,” transporting **glucose**, **2-deoxyglucose**, **N-acetylglucosamine**, **N-acetylmannosamine**, and **galactosamine**.
    reference_section_type: OTHER
  - statement: >-
      The mannose PTS shows relatively high affinity for glucose (Km ~15 uM),
      acting as an alternative glucose transport route in E. coli.
    supporting_text: |-
      A 2023 review focusing on *E. coli* glucose transport states that the **mannose PTS** shows **relatively high affinity for glucose (Km ≈ 15 µM)** and notes that E. coli encodes **15 distinct EII PTS complexes**.
    reference_section_type: OTHER
  - statement: >-
      The ManY/ManZ (IIC/IID) inner-membrane subcomplex is sufficient for phage
      lambda DNA penetration across the inner membrane, reinforcing a pore-like
      function for ManZ.
    supporting_text: |-
      **ManY (EIICMan)** and **ManZ (EIIDMan)**: inner-membrane components forming a tight complex; the **IIC/IID subcomplex** is sufficient for **phage DNA penetration** across the inner membrane.
    reference_section_type: OTHER
  - statement: >-
      The EIIDMan (ManZ) component is unusual and required not only for mannose
      transport but also for uptake/penetration of phage lambda DNA.
    supporting_text: |-
      EcoSal Plus (2005) provides an expert synthesis emphasizing that the **EIIDMan (ManZ)** component is “unusual” and required not only for mannose transport but also for **uptake/penetration of phage λ DNA**, strongly implying a specialized role in the membrane translocation apparatus beyond canonical PTS phosphorylation logic.
    reference_section_type: OTHER
- id: GO_REF:0000002
  title: Gene Ontology annotation through association of InterPro records with GO terms
  findings: []
- id: GO_REF:0000033
  title: Annotation inferences using phylogenetic trees
  findings: []
- id: GO_REF:0000044
  title: >-
    Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location
    vocabulary mapping, accompanied by conservative changes to GO terms applied by UniProt
  findings: []
- id: PMID:15919996
  title: Global topology analysis of the Escherichia coli inner membrane proteome.
  findings:
  - statement: >-
      ManZ was identified as an inner membrane protein with experimentally determined
      C-terminal topology using GFP/PhoA fusions in a global proteome-wide study.
    supporting_text: >-
      we established the periplasmic or cytoplasmic locations of the C termini for 601 inner membrane proteins
- id: PMID:16858726
  title: >-
    A complexomic study of Escherichia coli using two-dimensional blue native/SDS
    polyacrylamide gel electrophoresis.
  findings:
  - statement: >-
      ManZ was identified in membrane protein complexes by BN-PAGE/LC-MS/MS complexomics.
    supporting_text: >-
      the cytosolic and membrane protein complexes of Escherichia coli were separated.
      Then, the different partners of each protein complex were identified by LC-MS/MS.
- id: PMID:17309111
  title: >-
    Comparison of SDS- and methanol-assisted protein solubilization and digestion
    methods for Escherichia coli membrane proteome analysis by 2-D LC-MS/MS.
  findings:
  - statement: >-
      ManZ was identified as an integral membrane protein in the inner membrane fraction.
    supporting_text: >-
      ...to dissolve and analyze the inner membrane fraction of an Escherichia coli K12 cell lysate
- id: PMID:2951378
  title: >-
    The mannose permease of Escherichia coli consists of three different proteins.
    Amino acid sequence and function in sugar transport, sugar phosphorylation, and
    penetration of phage lambda DNA.
  findings:
  - statement: >-
      The mannose permease consists of three subunits: IIIMan (ManX), II-PMan (ManY), and
      II-MMan (ManZ). All three are required for sugar transport and phosphorylation.
      ManY and ManZ alone are sufficient for lambda DNA penetration.
    supporting_text: >-
      All three subunits are required for sugar transport and phosphorylation; II-PMan and II-MMan alone are
      sufficient for penetration of lambda DNA.
  - statement: >-
      II-PMan and II-MMan are integral membrane proteins that most likely form the
      transmembrane channel.
    supporting_text: >-
      II-PMan (28 kDa) is very hydrophobic;
      II-MMan (31 kDa) is moderately hydrophobic. Both are integral membrane proteins
      and most likely form the transmembrane channel.
- id: PMID:2999119
  title: >-
    The mannose-permease of the bacterial phosphotransferase system. Gene cloning
    and purification of the enzyme IIMan/IIIMan complex of Escherichia coli.
  findings:
  - statement: >-
      IIMan (ManZ) is a 27-kDa transmembrane protein. Together with IIIMan (ManX), both
      are required for phosphorylation of 2-deoxyglucose in vitro. IIMan alone is
      sufficient for lambda sensitivity.
    supporting_text: >-
      IIMan, a 27-kDa protein, is the transmembrane component of the complex.
      ...IIMan and IIIMan are both required for phosphorylation of
      2-deoxyglucose in vitro, while IIMan alone is sufficient to confer lambda
      sensitivity.
  - statement: >-
      The mannose-permease complex mediates PEP-dependent transport and phosphorylation
      of mannose, 2-deoxyglucose, and other hexoses.
    supporting_text: >-
      It mediates active transport concomitant with phosphorylation of mannose,
      2-deoxyglucose, and a number of other hexoses
- id: PMID:31209249
  title: >-
    Structure of the mannose transporter of the bacterial phosphotransferase system.
  findings:
  - statement: >-
      Cryo-EM structure reveals the ManYZ complex (ManY/EIIC + ManZ/EIID) as a
      multi-domain transmembrane transporter that uses an elevator mechanism for
      mannose transport, with CoreZ, VmotifZ, and ArmZ domains in ManZ.
    supporting_text: >-
      we have solved the cryo-EM structure of ManYZ at the inward-facing
      conformational state. Man-PTS transporters use an elevator mechanism for
      substrate transportation, in which the substrate-binding Core domain can
      undergo a rigid-body rotation across the cell membrane.
- id: PMID:353494
  title: >-
    E. coli K-12 pel mutants, which block phage lambda DNA injection, coincide with
    ptsM, which determines a component of a sugar transport system.
  findings:
  - statement: >-
      pel mutants that block phage lambda DNA injection map to the ptsM gene (manZ),
      establishing ManZ as required for lambda DNA penetration.
- id: PMID:4153999
  title: >-
    The role of phosphotransferase-mediated syntheses of fructose 1-phosphate and
    fructose 6-phosphate in the growth of Escherichia coli on fructose.
  findings:
  - statement: >-
      The mannose PTS can phosphorylate fructose to fructose 6-phosphate.
- id: PMID:4154035
  title: Genetical analysis of fructose utilization by Escherichia coli.
  findings:
  - statement: >-
      Genetic analysis demonstrates that the mannose PTS contributes to fructose
      utilization in E. coli.
- id: PMID:4604906
  title: >-
    Phosphotransferase-system enzymes as chemoreceptors for certain sugars in
    Escherichia coli chemotaxis.
  findings:
  - statement: >-
      PTS enzymes including the mannose permease function as chemoreceptors for sugar
      chemotaxis in E. coli.
- id: PMID:5545083
  title: >-
    Sugar transport. II. Characterization of constitutive membrane-bound enzymes
    II of the Escherichia coli phosphotransferase system.
  findings:
  - statement: >-
      Early characterization of constitutive membrane-bound enzymes II of the PTS,
      including the mannose-specific enzyme II.
- id: PMID:6252281
  title: Amino-sugar transport systems of Escherichia coli K12.
  findings:
  - statement: >-
      N-acetylglucosamine enters E. coli by two distinct PTS systems; one is the PtsM
      (mannose) system encoded by manZ. Glucosamine and mannose also enter by PtsM.
    supporting_text: >-
      N-Acetylglucosamine enters E. coli by two distinct phosphotransferase systems
      ...One of these is the PtsM system
- id: PMID:8774730
  title: Membrane topology of the mannose transporter of Escherichia coli K12.
  findings:
  - statement: >-
      Determined the membrane topology of ManZ, establishing it as a multi-pass
      integral inner membrane protein.

core_functions:
- description: >-
    ManZ is the EIID subunit of the mannose-specific phosphoenolpyruvate-dependent sugar
    phosphotransferase system (Man-PTS). Together with ManY (EIIC), it forms the transmembrane
    translocation channel that mediates PEP-dependent transport and concomitant phosphorylation
    of mannose and other hexose sugars. ManZ contributes to the complex-level mannose PTS
    transporter activity but does not independently catalyze this activity.
  molecular_function:
    id: GO:0022870
    label: protein-N(PI)-phosphohistidine-mannose phosphotransferase system transporter activity
  directly_involved_in:
  - id: GO:0009401
    label: phosphoenolpyruvate-dependent sugar phosphotransferase system
  - id: GO:0015761
    label: mannose transmembrane transport
  locations:
  - id: GO:0005886
    label: plasma membrane
  supported_by:
  - reference_id: PMID:2999119
    supporting_text: >-
      It mediates active transport concomitant with phosphorylation of mannose,
      2-deoxyglucose, and a number of other hexoses
  - reference_id: PMID:2951378
    supporting_text: >-
      The mannose permease of the bacterial phosphotransferase system mediates sugar
      transport across the cytoplasmic membrane concomitant with sugar phosphorylation.
      ...All three subunits are required for sugar transport and phosphorylation
  - reference_id: file:ECOLI/manZ/manZ-deep-research-falcon.md
    supporting_text: |-
      Together, these sources support that ManZ’s primary biological role is as part of a **PTS permease complex** whose functional output is **inner-membrane import of mannose-family substrates coupled to phosphorylation**, supporting growth on these sugars and contributing to global carbon uptake under varying conditions.

suggested_questions:
- question: >-
    Should ManZ have a dedicated GO annotation for its role as a receptor for bacteriophage
    lambda DNA injection? This is a well-characterized secondary function (PMID:353494,
    PMID:2951378) but there may not be an appropriate GO term for "phage DNA translocation
    channel" or similar.
- question: >-
    Should ManZ have a chemotaxis-related annotation based on PMID:4604906 showing PTS
    enzymes function as chemoreceptors? This may be an indirect effect mediated through
    the PTS signaling cascade rather than a direct molecular function of ManZ.
- question: >-
    The GOA qualifier for several transport annotations is "acts_upstream_of_or_within"
    rather than "involved_in". Given that ManZ is a direct structural component of the
    translocation channel, should these be upgraded to "involved_in"?