4jmn
From Proteopedia
Crystal structure of LD transpeptidase LdtMt1 from M. tuberculosis
Structural highlights
FunctionLDT1_MYCTU Generates 3->3 cross-links in peptidoglycan, catalyzing the cleavage of the mDap(3)-D-Ala(4) bond of a tetrapeptide donor stem and the formation of a bond between the carbonyl of mDap(3) of the donor stem and the side chain of mDap(3) of the acceptor stem. Is specific for donor substrates containing a stem tetrapeptide since it cannot use pentapeptide stems. Is thought to play a role in adaptation to the nonreplicative state of M.tuberculosis.[1] [2] Publication Abstract from PubMedThe modelling of peptidoglycan is responsible for key cellular processes in Mycobacterium tuberculosis such as cell growth, division and resuscitation from dormancy. The structure of M. tuberculosis peptidoglycan is atypical since it contains a majority of 3,3 cross-links synthesized by L,D-transpeptidases that replace the 4,3 cross-links formed by the D,D-transpeptidase activity of classical penicillin-binding proteins. Carbapenems inactivate these L,D-transpeptidases and in combination with clavulanic acid are bactericidal against extensively drug-resistant M. tuberculosis. Here, crystal structures of the L,D-transpeptidase LdtMt1 from M. tuberculosis in a ligand-free form and in complex with the carbapenem imipenem are reported. Elucidation of the structural features of LdtMt1 unveils analogies and differences between the two key transpeptidases of M. tuberculosis: LdtMt1 and LdtMt2. In addition, the structure of imipenem-inactivated LdtMt1 provides a detailed structural view of the interactions between a carbapenem drug and LdtMt1. By providing the key interactions in the binding of carbapenem to LdtMt1, this work will facilitate structure-guided discovery of L,D-transpeptidase inhibitors as novel antitubercular agents against drug-resistant M. tuberculosis. Structures of free and inhibited forms of the L,D-transpeptidase LdtMt1 from Mycobacterium tuberculosis.,Correale S, Ruggiero A, Capparelli R, Pedone E, Berisio R Acta Crystallogr D Biol Crystallogr. 2013 Sep;69(Pt 9):1697-706. doi:, 10.1107/S0907444913013085. Epub 2013 Aug 15. PMID:23999293[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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