id: Q88JU3
gene_symbol: quiC1
aliases:
- PP_2554
- 3-dehydroshikimate dehydratase
- DSD
taxon:
  id: NCBITaxon:160488
  label: Pseudomonas putida KT2440
description: 'QuiC1 is a 635-amino acid 3-dehydroshikimate dehydratase (EC 4.2.1.118)
  that catalyzes the conversion of 3-dehydroshikimate to protocatechuate (3,4-dihydroxybenzoate),
  a key reaction in quinate and shikimate degradation pathways. This enzyme is structurally
  distinct from previously characterized DSDs, consisting of a fusion of two domains:
  an N-terminal sugar phosphate isomerase-like domain that confers DSD activity, and
  a C-terminal hydroxyphenyl-pyruvate dioxygenase-like domain important for optimal
  activity. The enzyme requires divalent metal cations (preferentially Co2+) and functions
  as a homodimer. QuiC1 represents a novel structural variant of dehydroshikimate
  dehydratases found in pseudomonads, with applications in metabolic engineering for
  protocatechuate production.'
existing_annotations:
- term:
    id: GO:0016829
    label: lyase activity
  evidence_type: IEA
  original_reference_id: GO_REF:0000043
  review:
    summary: Correct and well-characterized - QuiC1 exhibits lyase activity by 
      catalyzing dehydration reaction
    action: ACCEPT
    reason: Accurately describes the enzyme mechanism. QuiC1 catalyzes the 
      elimination of water from 3-dehydroshikimate to form protocatechuate, 
      which is classified as lyase activity.
- term:
    id: GO:0046279
    label: 3,4-dihydroxybenzoate biosynthetic process
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  review:
    summary: Correct and specific - QuiC1 directly produces protocatechuate 
      (3,4-dihydroxybenzoate)
    action: ACCEPT
    reason: QuiC1 catalyzes the formation of protocatechuate as its primary 
      product, representing a key step in protocatechuate biosynthesis.
- term:
    id: GO:0046565
    label: 3-dehydroshikimate dehydratase activity
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  review:
    summary: Perfectly accurate - this is the precise enzymatic activity of 
      QuiC1
    action: ACCEPT
    reason: This is the exact molecular function of QuiC1 with experimentally 
      determined EC number 4.2.1.118.
- term:
    id: GO:0046872
    label: metal ion binding
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  review:
    summary: Correct and essential - QuiC1 requires divalent metal cations for 
      activity
    action: ACCEPT
    reason: QuiC1 requires divalent metal cations (Co(2+), Ni(2+), Mn(2+), 
      Mg(2+)) for catalytic activity, with specific metal binding sites 
      characterized.
- term:
    id: GO:0000287
    label: magnesium ion binding
  evidence_type: IDA
  original_reference_id: PMID:27706847
  review:
    summary: Experimentally confirmed - crystal structure shows specific Mg(2+) 
      binding sites
    action: ACCEPT
    reason: 'Crystal structure (PDB: 5HMQ) demonstrates specific magnesium binding
      sites, and biochemical assays confirm Mg(2+) can support catalytic activity.'
    supported_by:
    - reference_id: PMID:27706847
      supporting_text: Structurally diverse dehydroshikimate dehydratase 
        variants participate in microbial quinate catabolism.
- term:
    id: GO:0019631
    label: quinate catabolic process
  evidence_type: ISS
  original_reference_id: PMID:27706847
  review:
    summary: Core biological process - QuiC1 is essential for quinate 
      degradation pathway
    action: ACCEPT
    reason: QuiC1 catalyzes a central step in quinate catabolism, converting 
      pathway intermediate to protocatechuate for further degradation.
    supported_by:
    - reference_id: PMID:27706847
      supporting_text: Structurally diverse dehydroshikimate dehydratase 
        variants participate in microbial quinate catabolism.
- term:
    id: GO:0019633
    label: shikimate catabolic process
  evidence_type: ISS
  original_reference_id: PMID:27706847
  review:
    summary: Core biological process - QuiC1 participates in shikimate 
      degradation pathway
    action: ACCEPT
    reason: QuiC1 processes 3-dehydroshikimate, a key intermediate in shikimate 
      catabolism, enabling further degradation through protocatechuate.
    supported_by:
    - reference_id: PMID:27706847
      supporting_text: Structurally diverse dehydroshikimate dehydratase 
        variants participate in microbial quinate catabolism.
- term:
    id: GO:0046565
    label: 3-dehydroshikimate dehydratase activity
  evidence_type: IDA
  original_reference_id: PMID:27706847
  review:
    summary: Experimentally validated molecular function with detailed kinetic 
      characterization - preferred over IEA evidence
    action: ACCEPT
    reason: This represents the same function as the earlier IEA annotation but 
      with stronger experimental evidence (IDA) from biochemical 
      characterization.
    supported_by:
    - reference_id: PMID:27706847
      supporting_text: Structurally diverse dehydroshikimate dehydratase 
        variants participate in microbial quinate catabolism.
core_functions:
- description: 3-dehydroshikimate dehydratase that catalyzes conversion of 
    3-dehydroshikimate to protocatechuate in quinate and shikimate degradation 
    pathways
  molecular_function:
    id: GO:0046565
    label: 3-dehydroshikimate dehydratase activity
  directly_involved_in:
  - id: GO:0019631
    label: quinate catabolic process
  - id: GO:0019633
    label: shikimate catabolic process
  - id: GO:0046279
    label: 3,4-dihydroxybenzoate biosynthetic process
  supported_by:
  - reference_id: PMID:27706847
    supporting_text: Catalyzes the conversion of 3-dehydroshikimate to 
      protocatechuate (3,4-dihydroxybenzoate), a common intermediate of quinate 
      and shikimate degradation pathways
    full_text_unavailable: true
  - reference_id: PMID:27706847
    supporting_text: KM=331 uM for 3-dehydroshikimate
    full_text_unavailable: true
proposed_new_terms:
- proposed_name: two-domain dehydroshikimate dehydratase activity
  proposed_definition: The activity of dehydroshikimate dehydratases containing 
    both sugar phosphate isomerase-like and hydroxyphenyl-pyruvate 
    dioxygenase-like domains
  justification: QuiC1 represents a structurally distinct class of DSDs with 
    unique two-domain architecture not captured by existing GO terms
suggested_experiments:
- experiment_type: Domain deletion analysis
  description: Create N-terminal and C-terminal domain deletion mutants to 
    determine individual domain contributions to catalytic activity and 
    stability.
- experiment_type: Metal cofactor specificity analysis
  description: Systematic analysis of catalytic activity with different divalent
    metal cations to optimize enzyme performance for biotechnological 
    applications.
- experiment_type: Comparative structural analysis
  description: Compare QuiC1 structure with other DSD variants to understand 
    evolutionary relationships and structure-function determinants.
- experiment_type: Metabolic pathway engineering
  description: Engineer QuiC1 expression in heterologous hosts for enhanced 
    protocatechuate production from renewable feedstocks.
suggested_questions:
- question: What is the evolutionary origin of the two-domain architecture in 
    QuiC1-type dehydroshikimate dehydratases?
  experts:
  - Enzyme evolution specialists
  - Structural biologists
  - Comparative genomics researchers
- question: How does the C-terminal domain enhance DSD activity without 
    exhibiting dioxygenase function?
  experts:
  - Enzyme mechanism researchers
  - Protein domain specialists
  - Biochemical engineers
- question: Can QuiC1 be optimized for industrial protocatechuate production 
    through protein engineering?
  experts:
  - Metabolic engineers
  - Protein engineers
  - Industrial biotechnology specialists
- question: What are the physiological roles of different DSD variants in 
    Pseudomonas metabolism?
  experts:
  - Bacterial metabolism researchers
  - Systems biology specialists
  - Environmental microbiologists
references:
- id: GO_REF:0000043
  title: Gene Ontology annotation based on UniProtKB/Swiss-Prot keyword mapping
  findings: []
- id: GO_REF:0000120
  title: Combined Automated Annotation using Multiple IEA Methods.
  findings: []
- id: PMID:27706847
  title: Structurally diverse dehydroshikimate dehydratase variants participate 
    in microbial quinate catabolism.
  findings:
  - statement: QuiC1 characterized as 3-dehydroshikimate dehydratase in quinate 
      catabolism
    supporting_text: Structurally diverse dehydroshikimate dehydratase variants 
      participate in microbial quinate catabolism
status: COMPLETE