Cystathionine gamma-synthase MetB (CGS) (O-succinylhomoserine [thiol]-lyase); Catalyzes the formation of L-cystathionine from O-succinyl-L- homoserine (OSHS) and L-cysteine, via a gamma-replacement reaction (By similarity). In the absence of thiol, catalyzes gamma-elimination to form 2-oxobutanoate, succinate and ammonia.

Probable O-succinylhomoserine sulfhydrylase MetZ (OSH sulfhydrylase); Catalyzes the formation of L-homocysteine from O-succinyl-L- homoserine (OSHS) and hydrogen sulfide.

Ferredoxin-dependent sulfite reductase SirA; Catalyzes the reduction of sulfite to sulfide, a step in the biosynthesis of sulfur-containing amino acids and cofactors. Belongs to the nitrite and sulfite reductase 4Fe-4S domain family.

Sulfur carrier protein CysO; In its thiocarboxylated form (CysO-COSH), is the sulfur donor in the CysM-dependent cysteine biosynthetic pathway. May be of particular importance for cysteine biosynthesis in the persistent phase of M.tuberculosis; Belongs to the sulfur carrier protein CysO family.

S-sulfocysteine synthase; Catalyzes the synthesis of S-sulfocysteine, utilizing O- phosphoserine (OPS) and thiosulfate as substrates. To a lesser extent, can also use sulfide as donor substrate, producing L-cysteine. CysK2 thus provides a third metabolic route to cysteine, either directly using sulfide as donor or indirectly via S-sulfocysteine. S- sulfocysteine might also act as a signaling molecule triggering additional responses in redox defense in the pathogen upon exposure to reactive oxygen species during intracellular survival or dormancy. Cannot utilize thiocarboxylated CysO as [...]

Probable lyase; Rv3684, (MTV025.032), len: 346 aa. Probable lyase, and more specifically a cysteine synthase, highly similar to many lyases e.g. Q9K3N2|SCG20A.08c putative lyase from Streptomyces coelicolor (374 aa), FASTA scores: opt: 1469,E(): 3.7e-85, (63.35% identity in 341 aa overlap) (shorter 31 aa at N-terminus); Q9KT44|VC1061 cysteine synthase/ cystathionine beta-synthase family protein from Vibrio cholerae (355 aa), FASTA scores: opt: 1366, E(): 1.1e-78,(63.25% identity in 321 aa overlap); Q9I4R3|PA1061 hypothetical protein from Pseudomonas aeruginosa (365 aa),FASTA scores: op [...]

Possible phosphoserine aminotransferase SerC (PSAT); Catalyzes the reversible conversion of 3- phosphohydroxypyruvate to phosphoserine and of 3-hydroxy-2-oxo-4- phosphonooxybutanoate to phosphohydroxythreonine; Belongs to the class-V pyridoxal-phosphate-dependent aminotransferase family. SerC subfamily.

Rv0075, (MTV030.19), len: 390 aa. Probable aminotransferase, similar to many class-II pyridoxal-phosphate-dependent aminotransferases (MALY/PATB subfamily). Also similar to other proteins from Mycobacterium tuberculosis e.g. Rv2294, Rv0858c, etc.

Rv2294, (MTCY339.16c), len: 407 aa. Probable aminotransferase, similar to others in M. tuberculosis e.g. MTV030_19, also similar to PATB_BACSU|Q08432 putative aminotransferase b from Bacillus subtilis (387 aa), FASTA scores: opt: 563, E(): 2.8e-29, (31.4% identity in 408 aa overlap); and to MALY_ECOLI|P23256 maly protein from Escherichia coli (390 aa), FASTA scores: opt: 530, E(): 3.6e-27, (31.3% identity in 384 aa overlap). Belongs to class-II of pyridoxal-phosphate-dependent aminotransferases.