Bacterial SRP-dependent cotranslational membrane targeting

A reusable bacterial module for cotranslational targeting of hydrophobic nascent membrane proteins to the cytoplasmic membrane. An Ffh/4.5S-RNA signal recognition particle binds the ribosome-nascent-chain complex, the SRP receptor FtsY captures that complex at the membrane, and reciprocal GTPase activation promotes handoff to the SecYEG insertion machinery and dissociation of Ffh and FtsY. The boundary ends at this handoff; SecYEG-mediated translocation and insertion are downstream modules.

MODULE:bacterial_srp_cotranslational_targetingDRAFTCONCRETEBiological Processmodules/bacterial_srp_cotranslational_targeting.yaml
SRP-dependent cotranslational protein targeting to membraneGO:0006614
GO:0006614
SRP-dependent cotranslational protein targeting to membrane
GO:0006614 defines the biological-process boundary of the module.
GO:0048500
signal recognition particle
GO:0048500 grounds the Ffh/4.5S-RNA ribonucleoprotein particle.
RFAM:RF00169
Bacterial small signal recognition particle RNA
RF00169 grounds the conserved bacterial 4.5S SRP RNA family used as a required participant in nascent-chain recognition.
NCBIGene:26969983
Pseudomonas putida KT2440 ffs
NCBI Gene identifies the KT2440 4.5S SRP RNA as ffs, with aliases PP_RS22200 and PP_mr50, on reference chromosome NC_002947.4.
UniProtKB:P0AGD7
Escherichia coli K-12 Ffh
The reviewed E. coli Ffh entry provides a cross-species exemplar of the PTHR11564:SF5 signal-recognition-particle protein family.
UniProtKB:P10121
Escherichia coli K-12 FtsY
The reviewed E. coli FtsY entry provides a cross-species exemplar of the PTHR43134:SF1 bacterial SRP-receptor family.
file:PSEPK/ffh/ffh-ai-review.yaml
PSEPK Ffh gene review
Q88MV7 is the SRP RNA-binding GTPase component of the bacterial signal recognition particle.
file:PSEPK/ftsY/ftsY-ai-review.yaml
PSEPK FtsY gene review
Q88CR9 is the membrane-associated SRP receptor and partner GTPase.
file:projects/P_PUTIDA/batches/ppu03060_bacterial_srp_cotranslational_targeting.tsv
Pseudomonas putida KT2440 SRP-targeting batch
The focused batch records the exact KT2440 Ffh and FtsY implementations used as leaf exemplars.
file:projects/P_PUTIDA/deep-research/PSEPK__bacterial_srp_cotranslational_targeting__ppu03060-deep-research-openscientist.md
PSEPK SRP targeting module-pathway-taxon research
The species-aware retrieval finds the three-part module satisfied by Ffh, the ffs noncoding RNA, and FtsY, while separating downstream SecYEG, YidC, signal-peptidase, and parallel Tat components.

The bacterial 4.5S SRP RNA is represented at the conserved-family level by RFAM:RF00169, with the verified KT2440 ffs locus as one concrete exemplar. SecYEG is the receiving translocon, not a part of the SRP targeting module itself. The Pseudomonas putida KT2440 and Escherichia coli K-12 exemplars do not limit the reusable bacterial scope.

4Nodes
3Parts
0Variant Sets
0Variants
6Annotons
2Connections

Derived QC

Recommended-field compliance

100.0% recommended fields populated

All recommended fields populated.

Module deep research

✗ none found

No MODULE:bacterial_srp_cotranslational_targeting deep-research report alongside the module YAML.

Leaf nodes lacking representative members

✓ every leaf node grounds to a representative protein.

Template conformance

✓ every declared conforms_to bundle matches its template motif.

Reaction chaining (advisory)

✓ every PRECEDES step chains, or its break is acknowledged via chaining_status.

  • srp_nascent_chain_recognition → ftsy_receptor_engagement [NOT_CHECKED]
  • ftsy_receptor_engagement → srp_receptor_gtpase_cycle [NOT_CHECKED]

Gene-review completeness (2/4 grounded genes reviewed)

2 complete review(s) · 2 with deep research · 2 missing review · 0 reviewed but lacking deep research

Gene Review Complete Deep research
ffh Q88MV7 ✓ ✓ ✓
ftsY Q88CR9 ✓ ✓ ✓
Ffh (Escherichia coli K-12) P0AGD7 ✗ — —
FtsY (Escherichia coli K-12) P10121 ✗ — —

Details

Context
bacteriaNCBITaxon:2
Bacterial SRP-dependent cotranslational membrane targetingBiological Processbacterial_srp_cotranslational_targeting
SRP-dependent cotranslational protein targeting to membraneGO:0006614
Context
bacteriaNCBITaxon:2

Connections

Signal recognition by SRP precedes capture of the SRP-RNC complex by membrane-associated FtsY.
Receptor engagement precedes reciprocal GTPase activation, SecYEG handoff, and targeting-factor dissociation.
Part 1: nascent signal-sequence recognition by bacterial SRP
Ffh/4.5S-RNA nascent-chain recognitionBiological Processsrp_nascent_chain_recognition

Ffh associates with bacterial 4.5S SRP RNA to form SRP and recognizes hydrophobic signal sequences as they emerge from the translating ribosome.

SRP-dependent cotranslational protein targeting to membrane, signal sequence recognitionGO:0006617

Annotons

Ffh nascent signal-sequence binding
ffh_signal_sequence_binding
Participant: Family: Ffh/SRP54 family
Family:
Ffh/SRP54 familyPANTHER:PTHR11564:SF5
Representative Members: Ffh (Pseudomonas putida KT2440)UniProtKB:Q88MV7 Ffh (Escherichia coli K-12)UniProtKB:P0AGD7

Function

signal sequence bindingGO:0005048

Processes

SRP-dependent cotranslational protein targeting to membrane, signal sequence recognitionGO:0006617

Recognizes a hydrophobic signal sequence as it emerges from the translating ribosome.

Bacterial 4.5S SRP RNA
bacterial_srp_rna
Participant: Family: bacterial 4.5S signal recognition particle RNA family
Family:
bacterial 4.5S signal recognition particle RNA familyRFAM:RF00169
Representative Members: ffs 4.5S SRP RNA (Pseudomonas putida KT2440)NCBIGene:26969983

Processes

SRP-dependent cotranslational protein targeting to membrane, signal sequence recognitionGO:0006617

Scaffolds the bacterial SRP ribonucleoprotein and accelerates the Ffh-FtsY targeting cycle.

RFAM:RF00169
Bacterial small signal recognition particle RNA
RF00169 identifies the conserved bacterial small SRP RNA family.
PMID:11735405
Role of SRP RNA in the GTPase cycles of Ffh and FtsY
Kinetic analysis shows that bacterial SRP RNA accelerates Ffh-FtsY complex formation and coordinates their GTPase cycle.
Ffh binding to bacterial SRP RNA
ffh_srp_rna_binding
Participant: Family: Ffh/SRP54 family
Family:
Ffh/SRP54 familyPANTHER:PTHR11564:SF5
Representative Members: Ffh (Pseudomonas putida KT2440)UniProtKB:Q88MV7 Ffh (Escherichia coli K-12)UniProtKB:P0AGD7

Function

7S RNA bindingGO:0008312

Processes

SRP-dependent cotranslational protein targeting to membraneGO:0006614

Binds bacterial 4.5S SRP RNA to form the signal recognition particle ribonucleoprotein.

Part 2: membrane receptor engagement
FtsY engagement of the SRP-ribosome complexBiological Processftsy_receptor_engagement

Membrane-associated FtsY binds the SRP-ribosome-nascent-chain complex and positions it for the subsequent GTP-coupled handoff to SecYEG.

Annotons

FtsY SRP receptor
ftsy_srp_receptor
Participant: Family: bacterial FtsY SRP receptor family
Family:
bacterial FtsY SRP receptor familyPANTHER:PTHR43134:SF1
Representative Members: FtsY (Pseudomonas putida KT2440)UniProtKB:Q88CR9 FtsY (Escherichia coli K-12)UniProtKB:P10121

Function

signal recognition particle bindingGO:0005047

Processes

SRP-dependent cotranslational protein targeting to membraneGO:0006614

Locations

plasma membraneGO:0005886

Captures the SRP-ribosome-nascent-chain complex at the membrane.

Part 3: GTP-coupled handoff and targeting-factor recycling
Ffh/FtsY GTPase handoff cycleBiological Processsrp_receptor_gtpase_cycle

Ffh and FtsY form a reciprocal GTPase complex. Its ordered rearrangement and GTP hydrolysis promote transfer of the targeted ribosome-nascent-chain complex toward SecYEG and dissociation of the targeting factors.

Annotons

Ffh GTPase
ffh_gtpase
Participant: Family: Ffh/SRP54 family
Family:
Ffh/SRP54 familyPANTHER:PTHR11564:SF5
Representative Members: Ffh (Pseudomonas putida KT2440)UniProtKB:Q88MV7 Ffh (Escherichia coli K-12)UniProtKB:P0AGD7

Function

GTPase activityGO:0003924

Processes

SRP-dependent cotranslational protein targeting to membraneGO:0006614

Locations

plasma membraneGO:0005886

Catalyzes the Ffh half of reciprocal GTP hydrolysis after receptor engagement.

FtsY receptor GTPase
ftsy_gtpase
Participant: Family: bacterial FtsY SRP receptor family
Family:
bacterial FtsY SRP receptor familyPANTHER:PTHR43134:SF1
Representative Members: FtsY (Pseudomonas putida KT2440)UniProtKB:Q88CR9 FtsY (Escherichia coli K-12)UniProtKB:P10121

Function

GTPase activityGO:0003924

Processes

SRP-dependent cotranslational protein targeting to membraneGO:0006614

Locations

plasma membraneGO:0005886

Catalyzes the receptor half of reciprocal GTP hydrolysis during SecYEG handoff and complex dissociation.