Modulation of Escherichia coli serine acetyltransferase catalytic activity in the cysteine synthase complex. Issue 9 (17th April 2017)

• Record Type: Journal Article
• Authors: Benoni, Roberto; De Bei, Omar; Paredi, Gianluca; Hayes, Christopher S.; Franko, Nina; Mozzarelli, Andrea; Bettati, Stefano; Campanini, Barbara
• Is Part Of: FEBS letters. Volume 591:Issue 9(2017)
• Page Start: 1212
• Page End: 1224
• Publication Date: 2017-04-17
• Subjects: cysteine synthase -- protein–protein interaction -- serine acetyltransferase; Biochemistry -- Periodicals; Biophysics -- Periodicals; Molecular biology -- Periodicals; Biochimie -- Périodiques; Biochemistry; Biophysics; Molecular biology; Periodicals; 572.05
• DOI: 10.1002/1873-3468.12630
• Languages: English
• ISSNs: 0014-5793

Abstract

Abstract : In bacteria and plants, serine acetyltransferase (CysE) and O ‐acetylserine sulfhydrylase‐A sulfhydrylase (CysK) collaborate to synthesizel ‐Cys froml ‐Ser. CysE and CysK bind one another with high affinity to form the cysteine synthase complex (CSC). We demonstrate that bacterial CysE is activated when bound to CysK. CysE activation results from the release of substrate inhibition, with the K i forl ‐Ser increasing from 4 mm for free CysE to 16 mm for the CSC. Feedback inhibition of CysE byl‐ Cys is also relieved in the bacterial CSC. These findings suggest that the CysE active site is allosterically altered by CysK to alleviate substrate and feedback inhibition in the context of the CSC. Abstract : CysK and CysE interact to form the cysteine synthase complex (CSC). Within CSC, CysE is activated and CysK is partially inhibited. CysE activation within CSC is due to the release ofl‐ Ser inhibition. l‐ Cys weakens CSC and inhibits less efficiently CysE bound to CysK. CysE functional properties are affected by the conformation of its C‐terminus.