Enzymes
| UniProtKB help_outline | 1 proteins |
| Enzyme class help_outline |
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- Name help_outline O-phospho-L-serine Identifier CHEBI:57524 Charge -2 Formula C3H6NO6P InChIKeyhelp_outline BZQFBWGGLXLEPQ-REOHCLBHSA-L SMILEShelp_outline [NH3+][C@@H](COP([O-])([O-])=O)C([O-])=O 2D coordinates Mol file for the small molecule Search links Involved in 12 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline thiosulfate Identifier CHEBI:33542 Charge -1 Formula HO3S2 InChIKeyhelp_outline DHCDFWKWKRSZHF-UHFFFAOYSA-M SMILEShelp_outline [H]SS([O-])(=O)=O 2D coordinates Mol file for the small molecule Search links Involved in 22 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline phosphate Identifier CHEBI:43474 Charge -2 Formula HO4P InChIKeyhelp_outline NBIIXXVUZAFLBC-UHFFFAOYSA-L SMILEShelp_outline OP([O-])([O-])=O 2D coordinates Mol file for the small molecule Search links Involved in 983 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline S-sulfo-L-cysteine Identifier CHEBI:62225 Charge -1 Formula C3H6NO5S2 InChIKeyhelp_outline NOKPBJYHPHHWAN-REOHCLBHSA-M SMILEShelp_outline [NH3+][C@@H](CSS([O-])(=O)=O)C([O-])=O 2D coordinates Mol file for the small molecule Search links Involved in 2 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
| RHEA:52420 | RHEA:52421 | RHEA:52422 | RHEA:52423 | |
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| Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
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Publications
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CysK2 from Mycobacterium tuberculosis is an O-phospho-L-serine-dependent S-sulfocysteine synthase.
Steiner E.M., Boeth D., Loessl P., Vilaplana F., Schnell R., Schneider G.
Mycobacterium tuberculosis is dependent on cysteine biosynthesis, and reduced sulfur compounds such as mycothiol synthesized from cysteine serve in first-line defense mechanisms against oxidative stress imposed by macrophages. Two biosynthetic routes to l-cysteine, each with its own specific cyste ... >> More
Mycobacterium tuberculosis is dependent on cysteine biosynthesis, and reduced sulfur compounds such as mycothiol synthesized from cysteine serve in first-line defense mechanisms against oxidative stress imposed by macrophages. Two biosynthetic routes to l-cysteine, each with its own specific cysteine synthase (CysK1 and CysM), have been described in M. tuberculosis, but the function of a third putative sulfhydrylase in this pathogen, CysK2, has remained elusive. We present biochemical and biophysical evidence that CysK2 is an S-sulfocysteine synthase, utilizing O-phosphoserine (OPS) and thiosulfate as substrates. The enzyme uses a mechanism via a central aminoacrylate intermediate that is similar to that of other members of this pyridoxal phosphate-dependent enzyme family. The apparent second-order rate of the first half-reaction with OPS was determined as kmax/Ks = (3.97 × 10(3)) ± 619 M(-1) s(-1), which compares well to the OPS-specific mycobacterial cysteine synthase CysM with a kmax/Ks of (1.34 × 10(3)) ± 48.2. Notably, CysK2 does not utilize thiocarboxylated CysO as a sulfur donor but accepts thiosulfate and sulfide as donor substrates. The specificity constant kcat/Km for thiosulfate is 40-fold higher than for sulfide, suggesting an annotation as S-sulfocysteine synthase. Mycobacterial CysK2 thus provides a third metabolic route to cysteine, either directly using sulfide as donor or indirectly via S-sulfocysteine. Hypothetically, S-sulfocysteine could also act as a signaling molecule triggering additional responses in redox defense in the pathogen upon exposure to reactive oxygen species during dormancy. << Less
J. Bacteriol. 196:3410-3420(2014) [PubMed] [EuropePMC]
This publication is cited by 1 other entry.