Structural basis of chitin oligosaccharide deacetylation

Eduardo Andrés, David Albesa-Jové, Xevi Biarnés, Bruno M. Moerschbacher, Marcelo E. Guerin, Antoni Planas

Research output: Indexed journal article Articlepeer-review

77 Citations (Scopus)

Abstract

Cell signaling and other biological activities of chitooligosaccharides (COSs) seem to be dependent not only on the degree of polymerization, but markedly on the specific de-N-acetylation pattern. Chitin de-N-acetylases (CDAs) catalyze the hydrolysis of the acetamido group in GlcNAc residues of chitin, chitosan, and COS. A major challenge is to understand how CDAs specifically define the distribution of GlcNAc and GlcNH2 moieties in the oligomeric chain. We report the crystal structure of the Vibrio cholerae CDA in four relevant states of its catalytic cycle. The two enzyme complexes with chitobiose and chitotriose represent the first 3D structures of a CDA with its natural substrates in a productive mode for catalysis, thereby unraveling an induced-fit mechanism with a significant conformational change of a loop closing the active site. We propose that the deacetylation pattern exhibited by different CDAs is governed by critical loops that shape and differentially block accessible subsites in the binding cleft of CE4 enzymes. In the loop: The 3D structure of a chitin de-N-acetylase with its natural substrate (GlcNAc) 2 in a productive mode for catalysis has resulted in an induced-fit mechanism being identified in which a significant conformational change occurs in the loop closing the active site. In line with the proposed subsite-capping model, a complex with the longer substrate (GlcNAc)3 shows additional loop rearrangements.

Original languageEnglish
Pages (from-to)6882-6887
Number of pages6
JournalAngewandte Chemie - International Edition
Volume53
Issue number27
DOIs
Publication statusPublished - 1 Jul 2014

Keywords

  • binding modes
  • bioorganic chemistry
  • enzyme catalysis
  • enzyme-substrate complexes
  • structure elucidation

Fingerprint

Dive into the research topics of 'Structural basis of chitin oligosaccharide deacetylation'. Together they form a unique fingerprint.

Cite this