2b59

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spinqualitylabelsall models 2b59, resolution 2.11Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

The type II cohesin dockerin complex

Overview

Bacterial cell-surface attachment of macromolecular complexes maintains, the microorganism in close proximity to extracellular substrates and, allows for optimal uptake of hydrolytic byproducts. The cellulosome is a, large multienzyme complex used by many anaerobic bacteria for the, efficient degradation of plant cell-wall polysaccharides. The mechanism of, cellulosome retention to the bacterial cell surface involves a, calcium-mediated protein-protein interaction between the dockerin (Doc), module from the cellulosomal scaffold and a cohesin (Coh) module of, cell-surface proteins located within the proteoglycan layer. Here, we, report the structure of an ultra-high-affinity (K(a) = 1.44 x 10(10), M(-1)) complex between type II Doc, together with its neighboring X module, from the cellulosome scaffold of Clostridium thermocellum, and a type II, Coh module associated with the bacterial cell surface. Identification of X, module-Doc and X module-Coh contacts reveal roles for the X module in Doc, stability and enhanced Coh recognition. This extremely tight interaction, involves one face of the Coh and both helices of the Doc and comprises, significant hydrophobic character and a complementary extensive, hydrogen-bond network. This structure represents a unique mechanism for, cell-surface attachment in anaerobic bacteria and provides a rationale for, discriminating between type I and type II Coh modules.

About this Structure

2B59 is a Protein complex structure of sequences from Clostridium thermocellum and Clostridium thermocellum atcc 27405 with CA as ligand. Full crystallographic information is available from OCA.

Reference

Mechanism of bacterial cell-surface attachment revealed by the structure of cellulosomal type II cohesin-dockerin complex., Adams JJ, Pal G, Jia Z, Smith SP, Proc Natl Acad Sci U S A. 2006 Jan 10;103(2):305-10. Epub 2005 Dec 29. PMID:16384918

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