8F7N

Crystal structure of chemoreceptor McpZ ligand sensing domain

8F7N の概要

• エントリーDOI: 10.2210/pdb8f7n/pdb
• 分子名称: Methyl-accepting chemotaxis protein, YTTERBIUM (III) ION (3 entities in total)
• 機能のキーワード: mcp (methyl-accepting chemotaxis protein), chemotaxis, chemoreceptor, signaling protein
• 由来する生物種: Sinorhizobium meliloti
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 43532.56

構造登録者

Salar, S.,Schubot, F.D. (登録日: 2022-11-19, 公開日: 2023-07-05, 最終更新日: 2023-10-04)

主引用文献

Salar, S.,Ball, N.E.,Baaziz, H.,Nix, J.C.,Sobe, R.C.,Compton, K.K.,Zhulin, I.B.,Brown, A.M.,Scharf, B.E.,Schubot, F.D.
The structural analysis of the periplasmic domain of Sinorhizobium meliloti chemoreceptor McpZ reveals a novel fold and suggests a complex mechanism of transmembrane signaling.
Proteins, 91:1394-1406, 2023

PubMed Abstract: Chemotaxis is a fundamental process whereby bacteria seek out nutrient sources and avoid harmful chemicals. For the symbiotic soil bacterium Sinorhizobium meliloti, the chemotaxis system also plays an essential role in the interaction with its legume host. The chemotactic signaling cascade is initiated through interactions of an attractant or repellent compound with chemoreceptors or methyl-accepting chemotaxis proteins (MCPs). S. meliloti possesses eight chemoreceptors to mediate chemotaxis. Six of these receptors are transmembrane proteins with periplasmic ligand-binding domains (LBDs). The specific functions of McpW and McpZ are still unknown. Here, we report the crystal structure of the periplasmic domain of McpZ (McpZPD) at 2.7 Å resolution. McpZPD assumes a novel fold consisting of three concatenated four-helix bundle modules. Through phylogenetic analyses, we discovered that this helical tri-modular domain fold arose within the Rhizobiaceae family and is still evolving rapidly. The structure, offering a rare view of a ligand-free dimeric MCP-LBD, reveals a novel dimerization interface. Molecular dynamics calculations suggest ligand binding will induce conformational changes that result in large horizontal helix movements within the membrane-proximal domains of the McpZPD dimer that are accompanied by a 5 Å vertical shift of the terminal helix toward the inner cell membrane. These results suggest a mechanism of transmembrane signaling for this family of MCPs that entails both piston-type and scissoring movements. The predicted movements terminate in a conformation that closely mirrors those observed in related ligand-bound MCP-LBDs.

PubMed: 37213073
DOI: 10.1002/prot.26510

実験手法

X-RAY DIFFRACTION (2.7 Å)