6gi3

Structure of Lytic Transglycosylase MltE mutant S73A from E.coli

spinqualitylabelsall models 6gi3, resolution 1.38Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6gi3 is a 1 chain structure with sequence from "bacillus_coli"_migula_1895 "bacillus coli" migula 1895. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: TRS Gene: emtA, mltE, sltZ, ycgP, b1193, JW5821 ("Bacillus coli" Migula 1895) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [EMTA_ECOLI] Murein-degrading enzyme. May play a role in recycling of muropeptides during cell elongation and/or cell division. Preferentially cleaves at a distance of more than two disaccharide units from the ends of the glycan chain. Prefers cross-linked murein in vivo. Publication Abstract from PubMed Lytic transglycosylases (LTs) are bacterial enzymes that catalyze the cleavage of the glycan strands of the bacterial cell wall. The mechanism of this cleavage is a remarkable intramolecular transacetalization reaction, accomplished by an ensemble of active-site residues. Because the LT reaction occurs in parallel with the cell wall bond-forming reactions catalyzed by the penicillin-binding proteins, simultaneous inhibition of both enzymes can be particularly bactericidal to Gram-negative bacteria. The MltE lytic transglycosylase is the smallest of the eight LTs encoded by the Escherichia coli genome. Prior crystallographic and computational studies identified four active-site residues-E64, S73, S75, and Y192-as playing roles in catalysis. Each of these four residues was individually altered by mutation to give four variant enzymes (E64Q, S73A, S75A, and Y192F). All four variants showed reduced catalytic activity [soluble wild type (100%) > soluble Y192F and S75A (both 40%) > S73A (4%) > E64Q (</=1%)]. The crystal structure of each variant protein was determined at the resolution of 2.12 A for E64Q, 2.33 A for Y192F, 1.38 A for S73A, and 1.35 A for S75A. These variants show alteration of the hydrogen-bond interactions of the active site. Within the framework of a prior computational study of the LT mechanism, we suggest the mechanistic role of these four active-site residues in MltE catalysis. A Structural Dissection of the Active Site of the Lytic Transglycosylase MltE from Escherichia coli.,Dik DA, Batuecas MT, Lee M, Mahasenan KV, Marous DR, Lastochkin E, Fisher JF, Hermoso JA, Mobashery S Biochemistry. 2018 Sep 26. doi: 10.1021/acs.biochem.8b00800. PMID:30256085 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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