2g0u
From Proteopedia
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Solution Structure of Monomeric BsaL, the Type III Secretion Needle Protein of Burkholderia pseudomallei
Overview
Many gram-negative bacteria that are important human pathogens possess, type III secretion systems as part of their required virulence factor, repertoire. During the establishment of infection, these pathogens, coordinately assemble greater than 20 different proteins into a, macromolecular structure that spans the bacterial inner and outer, membranes and, in many respects, resembles and functions like a syringe., This type III secretion apparatus (TTSA) is used to inject proteins into a, host cell's membrane and cytoplasm to subvert normal cellular processes., The external portion of the TTSA is a needle that is composed of a single, type of protein that is polymerized in a helical fashion to form an, elongated tube with a central channel of 2-3 nm in diameter. TTSA needle, proteins from a variety of bacterial pathogens share sequence, conservation; however, no atomic structure for any TTSA needle protein is, yet available. Here, we report the structure of a TTSA needle protein, called BsaL from Burkholderia pseudomallei determined by nuclear magnetic, resonance (NMR) spectroscopy. The central part of the protein assumes a, helix-turn-helix core domain with two well-defined alpha-helices that are, joined by an ordered, four-residue linker. This forms a two-helix bundle, that is stabilized by interhelix hydrophobic contacts. Residues that flank, this presumably exposed core region are not completely disordered, but, adopt a partial helical conformation. The atomic structure of BsaL and its, sequence homology with other TTSA needle proteins suggest potentially, unique structural dynamics that could be linked with a universal mechanism, for control of type III secretion in diverse gram-negative bacterial, pathogens.
About this Structure
2G0U is a Single protein structure of sequence from Burkholderia pseudomallei. Full crystallographic information is available from OCA.
Reference
Solution structure of monomeric BsaL, the type III secretion needle protein of Burkholderia pseudomallei., Zhang L, Wang Y, Picking WL, Picking WD, De Guzman RN, J Mol Biol. 2006 Jun 2;359(2):322-30. Epub 2006 Mar 30. PMID:16631790
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