1nbc
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(New page: 200px<br /><applet load="1nbc" size="450" color="white" frame="true" align="right" spinBox="true" caption="1nbc, resolution 1.75Å" /> '''BACTERIAL TYPE 3A CE...)
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Revision as of 19:59, 20 November 2007
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BACTERIAL TYPE 3A CELLULOSE-BINDING DOMAIN
Overview
The crystal structure of a family-III cellulose-binding domain (CBD) from, the cellulosomal scaffoldin subunit of Clostridium thermocellum has been, determined at 1.75 A resolution. The protein forms a nine-stranded beta, sandwich with a jelly roll topology and binds a calcium ion. conserved, surface-exposed residues map into two defined surfaces located on opposite, sides of the molecule. One of these faces is dominated by a planar linear, strip of aromatic and polar residues which are proposed to interact with, crystalline cellulose. The other conserved residues are contained in a, shallow groove, the function of which is currently unknown, and which has, not been observed previously in other families of CBDs. On the basis of, modeling studies combined with comparisons of recently determined NMR, structures for other CBDs, a general model for the binding of CBDs to, cellulose is presented. Although the proposed binding of the CBD to, cellulose is essentially a surface interaction, specific types and, combinations of amino acids appear to interact selectively with glucose, moieties positioned on three adjacent chains of the cellulose surface. The, major interaction is characterized by the planar strip of aromatic, residues, which align along one of the chains. In addition, polar amino, acid residues are proposed to anchor the CBD molecule to two other, adjacent chains of crystalline cellulose.
About this Structure
1NBC is a Single protein structure of sequence from Clostridium thermocellum with CA as ligand. Full crystallographic information is available from OCA.
Reference
Crystal structure of a bacterial family-III cellulose-binding domain: a general mechanism for attachment to cellulose., Tormo J, Lamed R, Chirino AJ, Morag E, Bayer EA, Shoham Y, Steitz TA, EMBO J. 1996 Nov 1;15(21):5739-51. PMID:8918451
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