3LT7

A transition from strong right-handed to canonical left-handed supercoiling in a conserved coiled coil segment of trimeric autotransporter adhesins - the M3 mutant structure

Summary for 3LT7

• Entry DOI: 10.2210/pdb3lt7/pdb
• Related: 3H7X 3H7Z 3LT6
• Descriptor: Adhesin yadA (2 entities in total)
• Functional Keywords: adhesion, coiled coil, trimeric autotransporter, cell adhesion, cell membrane, cell outer membrane, membrane, plasmid, virulence
• Biological source: Yersinia enterocolitica
• Cellular location: Cell outer membrane: P31489
• Total number of polymer chains: 6
• Total formula weight: 43837.52

Authors

Zeth, K.,Hernandez-Alvarez, B.,Lupas, A.N. (deposition date: 2010-02-15, release date: 2010-03-31, Last modification date: 2024-02-21)

Primary citation

Alvarez, B.H.,Gruber, M.,Ursinus, A.,Dunin-Horkawicz, S.,Lupas, A.N.,Zeth, K.
A transition from strong right-handed to canonical left-handed supercoiling in a conserved coiled-coil segment of trimeric autotransporter adhesins.
J.Struct.Biol., 170:236-245, 2010

PubMed Abstract: 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.

PubMed: 20178846
DOI: 10.1016/j.jsb.2010.02.009

Experimental method

X-RAY DIFFRACTION (1.5 Å)