4bzp
Structure of the Mycobacterium tuberculosis APS kinase CysC in complex with ADP
Structural highlights
FunctionA5U1Y4_MYCTA APS kinase catalyzes the synthesis of activated sulfate.[ARBA:ARBA00002357] Catalyzes the synthesis of activated sulfate.[HAMAP-Rule:MF_00065] With CysD forms the ATP sulfurylase (ATPS) that catalyzes the adenylation of sulfate producing adenosine 5'-phosphosulfate (APS) and diphosphate, the first enzymatic step in sulfur assimilation pathway. APS synthesis involves the formation of a high-energy phosphoric-sulfuric acid anhydride bond driven by GTP hydrolysis by CysN coupled to ATP hydrolysis by CysD.[HAMAP-Rule:MF_00062] Publication Abstract from PubMedIn Mycobacterium tuberculosis the sulfate activating complex provides a key branching point in sulfate assimilation. The complex consists of two polypeptide chains, CysD and CysN. CysD is an ATP sulfurylase that, with the energy provided by the GTPase activity of CysN, forms adenosine-5'-phosphosulfate (APS) which can then enter the reductive branch of sulfate assimilation leading to the biosynthesis of cysteine. The CysN polypeptide chain also contains an APS kinase domain (CysC) that phosphorylates APS leading to 3'-phosphoadenosine-5'-phosphosulfate, the sulfate donor in the synthesis of sulfolipids. We have determined the crystal structures of CysC from M. tuberculosis as a binary complex with ADP, and as ternary complexes with ADP and APS and the ATP mimic AMP-PNP and APS, respectively, to resolutions of 1.5 A, 2.1 A and 1.7 A, respectively. CysC shows the typical APS kinase fold, and the structures provide comprehensive views of the catalytic machinery, conserved in this enzyme family. Comparison to the structure of the human homolog show highly conserved APS and ATP binding sites, questioning the feasibility of the design of specific inhibitors of mycobacterial CysC. Residue Cys556 is part of the flexible lid region that closes off the active site upon substrate binding. Mutational analysis revealed this residue as one of the determinants controlling lid closure and hence binding of the nucleotide substrate. Crystal Structures of the Kinase Domain of the Sulfate-Activating Complex in Mycobacterium tuberculosis.,Poyraz O, Brunner K, Lohkamp B, Axelsson H, Hammarstrom LG, Schnell R, Schneider G PLoS One. 2015 Mar 25;10(3):e0121494. doi: 10.1371/journal.pone.0121494., eCollection 2015. PMID:25807013[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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