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Publication Abstract from PubMed

Laminarin is an abundant brown algal storage polysaccharide. Marine microorganisms, such as Zobellia galactanivorans, produce laminarinases for its degradation, which are important for the processing of this organic matter in the ocean carbon cycle. These laminarinases are often modular, as is the case with ZgLamC which has an N-terminal GH16 module, a central family 6 carbohydrate-binding module (CBM) and a C-terminal PorSS module. To date no studies have characterized a true marine laminarin binding CBM6 with its natural carbohydrate ligand. The crystal structure of ZgLamCCBM 6 indicates that this CBM has two clefts for binding sugar (Variable loop site, VLS, and concave face site, CFS). The ZgLamCCBM 6 VLS binds in an exo-manner and the CFS interacts in an endo manner with laminarin. Isothermal titration calorimetry experiments on native and mutant ZgLamCCBM 6 confirm that these binding sites have different modes of recognition for laminarin, in agreement with the 'regional model' postulated for CBM6 binding modules. Based on isothermal titration calorimetry data and structural data we propose a model of ZgLamCCBM 6 interacting with different chains of laminarin in a multivalent manner, forming a complex cross-linked protein-polysaccharide network. This article is protected by copyright. All rights reserved.

Unraveling the multivalent binding of a marine family 6 carbohydrate-binding module with its native laminarin ligand.,Jam M, Ficko-Blean E, Labourel A, Larocque R, Czjzek M, Michel G FEBS J. 2016 Mar 9. doi: 10.1111/febs.13707. PMID:26959085^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.