1mt0
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(New page: 200px<br /><applet load="1mt0" size="450" color="white" frame="true" align="right" spinBox="true" caption="1mt0, resolution 2.6Å" /> '''ATP-binding domain of...)
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Revision as of 19:33, 20 November 2007
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ATP-binding domain of haemolysin B from Escherichia coli
Overview
The ABC-transporter haemolysin B is a central component of the secretion, machinery that translocates the toxin, haemolysin A, in a Sec-independent, fashion across both membranes of E. coli. Here, we report the X-ray, crystal structure of the nucleotide-binding domain (NBD) of HlyB. The, molecule shares the common overall architecture of ABC-transporter NBDs., However, the last three residues of the Walker A motif adopt a 3(10), helical conformation, stabilized by a bound anion. In consequence, this, results in an unusual interaction between the Walker A lysine residue and, the Walker B glutamate residue. As these residues are normally required to, be available for ATP binding, for catalysis and for dimer formation of ABC, domains, we suggest that this conformation may represent a latent, monomeric form of the NBD. Surprisingly, comparison of available NBD, structures revealed a structurally diverse region (SDR) of about 30, residues within the helical arm II domain, unique to each of the eight, NBDs analyzed. As this region interacts with the transmembrane part of, ABC-transporters, the SDR helps to explain the selectivity and/or, targeting of different NBDs to their cognate transmembrane domains.
About this Structure
1MT0 is a Single protein structure of sequence from Escherichia coli with SO4 as ligand. Full crystallographic information is available from OCA.
Reference
Crystal structure of the nucleotide-binding domain of the ABC-transporter haemolysin B: identification of a variable region within ABC helical domains., Schmitt L, Benabdelhak H, Blight MA, Holland IB, Stubbs MT, J Mol Biol. 2003 Jul 4;330(2):333-42. PMID:12823972
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