2pi8
From Proteopedia
Crystal structure of E. coli MltA with bound chitohexaose
Structural highlights
FunctionMLTA_ECOLI Murein-degrading enzyme. May play a role in recycling of muropeptides during cell elongation and/or cell division. Degrades murein glycan strands and insoluble, high-molecular weight murein sacculi. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedCrystal structures of an inactive mutant (D308A) of the lytic transglycosylase MltA from Escherichia coli have been determined in two different apo-forms, as well as in complex with the substrate analogue chitohexaose. The chitohexaose binds with all six saccharide residues in the active site groove, with an intact glycosidic bond at the bond cleavage center. Its binding induces a large reorientation of the two structural domains in MltA, narrowing the active site groove and allowing tight interactions of the oligosaccharide with residues from both domains. The structures identify residues in MltA with key roles in the binding and recognition of peptidoglycan and confirm that Asp-308 is the single catalytic residue, acting as a general acid/base. Moreover, the structures suggest that catalysis involves a high energy conformation of the scissile glycosidic linkage and that the putative oxocarbenium ion intermediate is stabilized by the dipole moment of a nearby alpha-helix. Structure of Escherichia coli Lytic transglycosylase MltA with bound chitohexaose: implications for peptidoglycan binding and cleavage.,van Straaten KE, Barends TR, Dijkstra BW, Thunnissen AM J Biol Chem. 2007 Jul 20;282(29):21197-205. Epub 2007 May 14. PMID:17502382[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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