3asb
From Proteopedia
Crystal structure of PLP-bound LL-diaminopimelate aminotransferase from Chlamydia trachomatis
Structural highlights
Function[DAPAT_CHLTR] Involved in the synthesis of meso-diaminopimelate (m-DAP or DL-DAP), required for both lysine and peptidoglycan biosynthesis. Catalyzes the direct conversion of tetrahydrodipicolinate to LL-diaminopimelate, a reaction that requires three enzymes in E.coli. Is also able to use meso-diaminopimelate, cystathionine, lysine or ornithine as substrates.[1] Publication Abstract from PubMedWe have previously reported the structures of the native holo and substrate-bound forms of ll-diaminopimelate aminotransferase from Arabidopsis thaliana (AtDAP-AT). Here, we report the crystal and molecular structures of the ll-diaminopimelate aminotransferase from Chlamydia trachomatis (CtDAP-AT) in the apo-form and the pyridoxal-5'-phosphate-bound form. The molecular structure of CtDAP-AT shows that its overall fold is essentially identical with that of AtDAP-AT except that CtDAP-AT adopts an "open" conformation as opposed to the "closed" conformation of AtDAP-AT. Although AtDAP-AT and CtDAP-AT are approximately 40% identical in their primary sequence, they have major differences in their substrate specificities; AtDAP-AT is highly specific for LL-DAP, whereas CtDAP-AT accepts a wider range of substrates. Since all of the residues involved in substrate recognition are highly conserved between AtDAP-AT and CtDAP-AT, we propose that differences in flexibility of the loops lining the active-site region between the two enzymes likely account for the differences in substrate specificity. The Structure of ll-Diaminopimelate Aminotransferase from Chlamydia trachomatis: Implications for Its Broad Substrate Specificity.,Watanabe N, Clay MD, van Belkum MJ, Fan C, Vederas JC, James MN J Mol Biol. 2011 Aug 19;411(3):649-60. Epub 2011 Jun 21. PMID:21722650[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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