Crystal structure of Clostridium acetobutylicum Aspartate kinase (CaAK): An important allosteric enzyme for amino acids production

摘要: Aspartate kinase (AK) is an enzyme which tightly regulated through feedback control and responsible for the synthesis of 4-phospho-L-aspartate from L-aspartate. This intermediate step at important branch point where one path leads to lysine other threonine, methionine isoleucine. Concerted inhibition AK mediated by threonine varies between species. The crystal structure biotechnologically Clostridium acetobutylicum aspartate (CaAK; E.C. 2.7.2.4; Mw=48,030Da; 437aa; SwissProt: Q97MC0) has been determined 3A resolution. CaAK acquires a protein fold similar known structures AKs despite low sequence identity (<30%). It composed two domains: N-terminal catalytic domain (kinase) C-terminal regulatory further comprised small domains belonging ACT family. Pairwise comparison 12 molecules in asymmetric unit helped identify bending regions are vicinity ATP binding site involved movements domains. All adopt fully open T-state conformation leading formation three tetramers unique among structures. On basis comparative structural analysis, we discuss tetramer based on large conformational changes associated with described herein homologous target wide-spread pathogenic (toxin producing) bacteria such as tetani (64% identity) suggesting potential solved here be applied modeling drug interactions. may serve guide better understand engineer biosynthesis biotechnology industry.