CysK2 from Mycobacterium tuberculosis is an O-phospho-L-serine-dependent S-sulfocysteine synthase.

ABSTRACT: 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 sec

SUBMITTER: Steiner EM 

PROVIDER: S-EPMC4187678 | biostudies-literature | 2014 Oct

REPOSITORIES: biostudies-literature