Localization | Comment | Organism | GeneOntology No. | Textmining |
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Organism | UniProt | Comment | Textmining |
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Escherichia coli | - |
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Synonyms | Comment | Organism |
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CSC | - |
Escherichia coli |
General Information | Comment | Organism |
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physiological function | cysteine synthase complex CSC is comprised of the two enzymes that catalyze the final steps in cysteine biosynthesis: serine O-acetyltransferase, EC 2.3.1.30, which produces O-acetyl-L-serine, and O-acetyl-L-serine sulfhydrylase, EC 2.5.1.47, which converts it to cysteine. The system exhibits a contact-induced inactivation of half of each biomolecule, and exhibits a mechanism in which serine O-acetyltransferase interacts with O-acetyl-L-serine sulfhydrylase in a nonallosteric interaction involving its C-terminus. This early docking event appears to fasten the proteins in close proximity. The complex passes through at least three stable conformations in achieving its most stable configuration. Binding of a serine O-acetyltransferase C-terminal peptide is monophasic, and binding at one O-acetyl-L-serine sulfhydrylase active site does not prevent, or otherwise influence, binding at the second. The rate constants governing the first phase of the serine O-acetyltransferase binding reaction are remarkably similar to those for the binding of peptide, suggesting that early docking of serine O-acetyltransferase occurs primarily through the its C-terminus. The inability of the peptide to either induce isomerization or close the distal site suggests that serine O-acetyltransferase structure beyond its C-terminus is required to engage in isomerization and that closure of the unoccupied O-acetyl-L-serine sulfhydrylase active site may be coupled to the one or more isomerizations | Escherichia coli |