5OQ1

Crystal structure of Serratia marcescens ChiX (used as MR model for superior PDB 5OPZ)

Summary for 5OQ1

• Entry DOI: 10.2210/pdb5oq1/pdb
• Related: 5OPZ
• Descriptor: ChiX, ZINC ION, CHLORIDE ION, ... (4 entities in total)
• Functional Keywords: l-ala d-glu endopeptidase serratia marcescens chitinase secretion anomalous dispersion zinc enzyme, hydrolase
• Biological source: Serratia marcescens
• Total number of polymer chains: 2
• Total formula weight: 31135.57

Authors

Owen, R.A.,Fyfe, P.K.,Lodge, A.,Biboy, J.,Vollmer, W.,Hunter, W.N.,Sargent, F. (deposition date: 2017-08-10, release date: 2018-01-17, Last modification date: 2024-05-08)

Primary citation

Owen, R.A.,Fyfe, P.K.,Lodge, A.,Biboy, J.,Vollmer, W.,Hunter, W.N.,Sargent, F.
Structure and activity of ChiX: a peptidoglycan hydrolase required for chitinase secretion by Serratia marcescens.
Biochem. J., 475:415-428, 2018

PubMed Abstract: The Gram-negative bacterium secretes many proteins that are involved in extracellular chitin degradation. This so-called chitinolytic machinery includes three types of chitinase enzymes and a lytic polysaccharide monooxygenase. An operon has been identified in , , that is thought to be involved in the secretion of the chitinolytic machinery. Genetic evidence points to the ChiX protein being a key player in the secretion mechanism, since deletion of the gene in led to a mutant strain blocked for secretion of all members of the chitinolytic machinery. In this work, a detailed structural and biochemical characterisation of ChiX is presented. The high-resolution crystal structure of ChiX reveals the protein to be a member of the LAS family of peptidases. ChiX is shown to be a zinc-containing metalloenzyme, and assays demonstrate that ChiX is an l-Ala d-Glu endopeptidase that cleaves the cross-links in bacterial peptidoglycan. This catalytic activity is shown to be intimately linked with the secretion of the chitinolytic machinery, since substitution of the ChiX Asp-120 residue results in a variant protein that is both unable to digest peptidoglycan and cannot rescue the phenoytype of a mutant strain.

PubMed: 29229757
DOI: 10.1042/BCJ20170633

Experimental method

X-RAY DIFFRACTION (1.34 Å)