2PI8

Crystal structure of E. coli MltA with bound chitohexaose

Summary for 2PI8

• Entry DOI: 10.2210/pdb2pi8/pdb
• Related: 2AE0 2PIC 2PJJ
• Descriptor: Membrane-bound lytic murein transglycosylase A, 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose, PHOSPHATE ION, ... (4 entities in total)
• Functional Keywords: double-psi beta-barrel; protein-sugar complex; lytic transglycosylase, hydrolase
• Biological source: Escherichia coli
• Cellular location: Cell outer membrane; Lipid-anchor: P0A935
• Total number of polymer chains: 4
• Total formula weight: 160033.43

Authors

van Straaten, K.E.,Barends, T.R.M.,Dijkstra, B.W.,Thunnissen, A.M.W.H. (deposition date: 2007-04-13, release date: 2007-05-08, Last modification date: 2024-10-16)

Primary citation

van Straaten, K.E.,Barends, T.R.M.,Dijkstra, B.W.,Thunnissen, A.M.W.H.
Structure of Escherichia coli Lytic transglycosylase MltA with bound chitohexaose: implications for peptidoglycan binding and cleavage
J.Biol.Chem., 282:21197-21205, 2007

PubMed Abstract: Crystal 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.

PubMed: 17502382
DOI: 10.1074/jbc.M701818200

Experimental method

X-RAY DIFFRACTION (2.25 Å)