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Publication Abstract from PubMed

Bacterial cellulose (BC) is synthesized and exported through the cell membrane via a large protein complex (terminal complex) that consists of three or four subunits. BcsC is a little-studied subunit considered to export BC to the extracellular matrix. It is predicted to have two domains: a tetratrico peptide repeat (TPR) domain and a beta-barrelled outer membrane domain. Here we report the crystal structure of the N-terminal part of BcsC-TPR domain (Asp24-Arg272) derived from Enterobacter CJF-002. Unlike most TPR-containing proteins which have continuous TPR motifs, this structure has an extra alpha-helix between two clusters of TPR motifs. Five independent molecules in the crystal had three different conformations that varied at the hinge of the inserted alpha-helix. Such structural feature indicates that the inserted alpha-helix confers flexibility to the chain and changes the direction of the TPR super-helix, which was also suggested by structural analysis of BcsC-TPR (Asp24-Leu664) in solution by size exclusion chromatography-small-angle X-ray scattering. The flexibility at the alpha-helical hinge may play important role for exporting glucan chains.

Crystal structure of the flexible tandem repeat domain of bacterial cellulose synthesis subunit C.,Nojima S, Fujishima A, Kato K, Ohuchi K, Shimizu N, Yonezawa K, Tajima K, Yao M Sci Rep. 2017 Oct 12;7(1):13018. doi: 10.1038/s41598-017-12530-0. PMID:29026093^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.