3lt6

A transition from strong right-handed to canonical left-handed supercoiling in a conserved coiled coil segment of trimeric autotransporter adhesins - the Mutant 4 structure

spinqualitylabelsall models 3lt6, resolution 1.80Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3lt6 is a 6 chain structure with sequence from Yersinia enterocolitica. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. NonStd Res: MSE Related: 3h7x, 3h7z, 3lt7 Gene: yadA, invA, yop1, yopA (Yersinia enterocolitica) Resources: FirstGlance, OCA, RCSB, PDBsum Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Trimeric autotransporter adhesins (TAAs) represent an important class of pathogenicity factors in proteobacteria. Their defining feature is a conserved membrane anchor, which forms a 12-stranded beta-barrel through the outer membrane. The proteins are translocated through the pore of this barrel and, once export is complete, the pore is occluded by a three-stranded coiled coil with canonical heptad (7/2) sequence periodicity. In many TAAs this coiled coil is extended by a segment of varying length, which has pentadecad (15/4) periodicity. We used X-ray crystallography and biochemical methods to analyze the transition between these two periodicities in the coiled-coil stalk of the Yersinia adhesin YadA. Our results show how the strong right-handed supercoil of the 15/4-periodic part locally undergoes further over-winding to 19/5, before switching at a fairly constant rate over 14 residues to the canonical left-handed supercoil of the 7/2-periodic part. The transition region contains two YxD motifs, which are characteristic for right-handed coiled-coil segments of TAAs. This novel coiled-coil motif forms a defined network of inter- and intrahelical hydrogen bonds, thus serving as a structural determinant. Supercoil fluctuations have hitherto been described in coiled coils whose main sequence periodicity is disrupted locally by discontinuities. Here we present the first detailed analysis of two fundamentally different coiled-coil periodicities being accommodated in the same structure. A transition from strong right-handed to canonical left-handed supercoiling in a conserved coiled-coil segment of trimeric autotransporter adhesins.,Alvarez BH, Gruber M, Ursinus A, Dunin-Horkawicz S, Lupas AN, Zeth K J Struct Biol. 2010 May;170(2):236-45. Epub 2010 Feb 21. PMID:20178846 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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