cysD

UniProt ID: Q88NA9
Organism: Pseudomonas putida (strain ATCC 47054 / DSM 6125 / CFBP 8728 / NCIMB 11950 / KT2440)
Review Status: DRAFT
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Gene Description

CysD is the catalytic subunit 2 of the proteobacterial sulfate adenylyltransferase complex. Together with the regulatory GTPase subunit CysNC, it uses ATP to adenylate sulfate and form adenosine 5'-phosphosulfate (APS), initiating the reductive branch of sulfate assimilation.

Existing Annotations Review

GO Term Evidence Action Reason
GO:0000103 sulfate assimilation
IEA
GO_REF:0000120 		ACCEPT
Summary: Correct pathway assignment for sulfate activation.
Reason: CysD performs the first committed chemical transformation in the sulfate-to-sulfide assimilation route.
Supporting Evidence:
file:PSEPK/cysD/cysD-uniprot.txt
the first enzymatic step in sulfur assimilation pathway.
GO:0003824 catalytic activity
IEA
GO_REF:0000002 		MARK AS OVER ANNOTATED
Summary: Correct but uninformative catalytic parent.
Reason: GO:0004781 identifies the sulfate and ATP-dependent reaction.
GO:0004781 sulfate adenylyltransferase (ATP) activity
IEA
GO_REF:0000120 		ACCEPT
Summary: Correct substrate-specific activity for the CysD/CysNC complex.
Reason: The reviewed Q88NA9 record assigns EC 2.7.7.4 and specifies ATP-dependent conversion of sulfate to APS.
Supporting Evidence:
file:PSEPK/cysD/cysD-uniprot.txt
Reaction=sulfate + ATP + H(+) = adenosine 5'-phosphosulfate +
GO:0070814 hydrogen sulfide biosynthetic process
IEA
GO_REF:0000120 		ACCEPT
Summary: Correct downstream process assignment.
Reason: APS formation supplies the first intermediate of the assimilatory route that reduces sulfate to sulfide.

Core Functions

Catalyzes ATP-dependent adenylation of sulfate to APS as the catalytic subunit of the CysD/CysNC ATP sulfurylase complex.

Molecular Function:
sulfate adenylyltransferase (ATP) activity
Directly Involved In:
sulfate assimilation
Supporting Evidence:
  • file:PSEPK/cysD/cysD-uniprot.txt
    Reaction=sulfate + ATP + H(+) = adenosine 5'-phosphosulfate +
  • PMID:16387658
    Proteobacterial ATPS overcomes this energetically unfavorable reaction

References

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Suggested Questions for Experts

Q: Does the KT2440 CysD/CysNC complex have the same GTP-coupling kinetics and subunit stoichiometry as the characterized Pseudomonas syringae enzyme?

Suggested Experiments

Experiment: Reconstitute Q88NA9 with Q88NA8 and measure APS formation while varying ATP, GTP, sulfate, and the two subunit concentrations.

Type: reconstituted enzyme kinetics

📚 Additional Documentation

Notes

(cysD-notes.md)

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