3U0C

Crystal structure of N-terminal region of Type III Secretion First Translocator IpaB (residues 74-224)

3U0C の概要

• エントリーDOI: 10.2210/pdb3u0c/pdb
• 関連するPDBエントリー: 3TUL
• 分子名称: Invasin ipaB (2 entities in total)
• 機能のキーワード: translocator, type three secretion system, coiled-coil, virulence, cell invasion
• 由来する生物種: Shigella flexneri
• 細胞内の位置: Secreted: P18011
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 44916.86

構造登録者

Barta, M.L.,Geisbrecht, B.V. (登録日: 2011-09-28, 公開日: 2012-02-15, 最終更新日: 2024-02-28)

主引用文献

Barta, M.L.,Dickenson, N.E.,Patil, M.,Keightley, A.,Wyckoff, G.J.,Picking, W.D.,Picking, W.L.,Geisbrecht, B.V.
The Structures of Coiled-Coil Domains from Type III Secretion System Translocators Reveal Homology to Pore-Forming Toxins.
J.Mol.Biol., 417:395-405, 2012

PubMed Abstract: Many pathogenic Gram-negative bacteria utilize type III secretion systems (T3SSs) to alter the normal functions of target cells. Shigella flexneri uses its T3SS to invade human intestinal cells to cause bacillary dysentery (shigellosis) that is responsible for over one million deaths per year. The Shigella type III secretion apparatus is composed of a basal body spanning both bacterial membranes and an exposed oligomeric needle. Host altering effectors are secreted through this energized unidirectional conduit to promote bacterial invasion. The active needle tip complex of S. flexneri is composed of a tip protein, IpaD, and two pore-forming translocators, IpaB and IpaC. While the atomic structure of IpaD has been elucidated and studied, structural data on the hydrophobic translocators from the T3SS family remain elusive. We present here the crystal structures of a protease-stable fragment identified within the N-terminal regions of IpaB from S. flexneri and SipB from Salmonella enterica serovar Typhimurium determined at 2.1 Å and 2.8 Å limiting resolution, respectively. These newly identified domains are composed of extended-length (114 Å in IpaB and 71 Å in SipB) coiled-coil motifs that display a high degree of structural homology to one another despite the fact that they share only 21% sequence identity. Further structural comparisons also reveal substantial similarity to the coiled-coil regions of pore-forming proteins from other Gram-negative pathogens, notably, colicin Ia. This suggests that these mechanistically separate and functionally distinct membrane-targeting proteins may have diverged from a common ancestor during the course of pathogen-specific evolutionary events.

PubMed: 22321794
DOI: 10.1016/j.jmb.2012.01.026

実験手法

X-RAY DIFFRACTION (2.05 Å)