Notes for VIBCH cds1 (Q9KT44)

Gene Summary

• UniProt: Q9KT44
• Gene: cds1 (VC_1061)
• Protein: L-cysteine desulfhydrase Cds1
• EC: 4.4.1.1
• Organism: Vibrio cholerae serotype O1 (strain ATCC 39315 / El Tor Inaba N16961)

PANTHER Family

This gene belongs to PANTHER subfamily PTHR10314:SF135 within family PTHR10314.

See family-level analysis: interpro/panther/PTHR10314/PTHR10314-notes.md

Key Finding: IBA Annotation Error

The IBA annotation GO:0019344 (L-cysteine biosynthetic process) is INCORRECT for this gene.

• Reason: SF135 (Cds1 subfamily) performs cysteine CATABOLISM (EC 4.4.1.1), not biosynthesis
• Branch length: 0.528 from root - longest branch, indicating significant functional divergence
• Correct annotations: GO:0019450 (cysteine catabolic process), GO:0080146 (L-cysteine desulfhydrase activity)

Gene-Specific Notes

Experimental Evidence (PMID:34283874 - Ma et al. 2021)

1. VC1061 (cds1) is the principal determinant of cysteine-derived H2S in V. cholerae
2. Genetic deletion (Δvc1061) drastically reduces H2S production from cysteine
3. CBS-derived H2S protects V. cholerae from oxidative stress (H2O2)
4. Δcbs shows ~10-fold lower viability under intense H2O2
5. H2S enhances catalase (KatB) activity at post-translational level
6. In adult mouse models, cbs mutant is outcompeted by WT under high-ROS conditions

Physiological Role

• Primary function: Produce H2S from cysteine degradation
• Secondary function: Protect against oxidative stress via H2S-mediated catalase enhancement
• Virulence factor: Required for host colonization under high-ROS conditions

Last updated: 2026-01-06