1nqe: Difference between revisions

Revision as of 21:06, 27 July 2008

This article has been automatically seeded. Changes to this page should pertain to the PDB entry only and not to the protein or biomolecule in general.

File:1nqe.png

Template:STRUCTURE 1nqe

OUTER MEMBRANE COBALAMIN TRANSPORTER (BTUB) FROM E. COLIOUTER MEMBRANE COBALAMIN TRANSPORTER (BTUB) FROM E. COLI

Template:ABSTRACT PUBMED 12652322

About this StructureAbout this Structure

1NQE is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.

ReferenceReference

Substrate-induced transmembrane signaling in the cobalamin transporter BtuB., Chimento DP, Mohanty AK, Kadner RJ, Wiener MC, Nat Struct Biol. 2003 May;10(5):394-401. PMID:12652322

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-'''OUTER MEMBRANE COBALAMIN TRANSPORTER (BTUB) FROM E. COLI'''
+===OUTER MEMBRANE COBALAMIN TRANSPORTER (BTUB) FROM E. COLI===
-==Overview==
+<!--
-The outer membranes of Gram-negative bacteria possess transport proteins essential for uptake of scarce nutrients. In TonB-dependent transporters, a conserved sequence of seven residues, the Ton box, faces the periplasm and interacts with the inner membrane TonB protein to energize an active transport cycle. A critical mechanistic step is the structural change in the Ton box of the transporter upon substrate binding; this essential transmembrane signaling event increases the affinity of the transporter for TonB and enables active transport to proceed. We have solved crystal structures of BtuB, the outer membrane cobalamin transporter from Escherichia coli, in the absence and presence of cyanocobalamin (vitamin B(12)). In these structures, the Ton box is ordered and undergoes a conformational change in the presence of bound substrate. Calcium has been implicated as a necessary factor for the high-affinity binding (K(d) approximately 0.3 nM) of cyanocobalamin to BtuB. We observe two bound calcium ions that order three extracellular loops of BtuB, thus providing a direct (and unusual) structural role for calcium.
+The line below this paragraph, {{ABSTRACT_PUBMED_12652322}}, adds the Publication Abstract to the page
+(as it appears on PubMed at http://www.pubmed.gov), where 12652322 is the PubMed ID number.
+-->
+{{ABSTRACT_PUBMED_12652322}}
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 [[Category: Outer membrane transport]]
 [[Category: Vitamin b12]]
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