2HP7

Structure of FliM provides insight into assembly of the switch complex in the bacterial flagella motor

2HP7 の概要

• エントリーDOI: 10.2210/pdb2hp7/pdb
• 分子名称: Flagellar motor switch protein FliM (2 entities in total)
• 機能のキーワード: bacterial chemotaxis, flagellar switch complex, signaling protein
• 由来する生物種: Thermotoga maritima
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 21044.14

構造登録者

Crane, B.R.,Park, S.,Lowder, B.,Bilwes, A.M.,Blair, D.F. (登録日: 2006-07-17, 公開日: 2006-08-08, 最終更新日: 2024-02-14)

主引用文献

Park, S.,Lowder, B.,Bilwes, A.M.,Blair, D.F.,Crane, B.R.
Structure of FliM provides insight into assembly of the switch complex in the bacterial flagella motor.
Proc.Natl.Acad.Sci.Usa, 103:11886-11891, 2006

PubMed Abstract: Bacteria switch the direction their flagella rotate to control movement. FliM, along with FliN and FliG, compose a complex in the motor that, upon binding phosphorylated CheY, reverses the sense of flagellar rotation. The 2.0-A resolution structure of the FliM middle domain (FliM(M)) from Thermotoga maritima reveals a pseudo-2-fold symmetric topology similar to the CheY phosphatases CheC and CheX. A variable structural element, which, in CheC, mediates binding to CheD (alpha2') and, in CheX, mediates dimerization (beta'(x)), has a truncated structure unique to FliM (alpha2'). An exposed helix of FliM(M) (alpha1) does not contain the catalytic residues of CheC and CheX but does include positions conserved in FliM sequences. Cross-linking experiments with site-directed cysteine mutants show that FliM self-associates through residues on alpha1 and alpha2'. CheY activated by BeF(3)(-) binds to FliM with approximately 40-fold higher affinity than CheY (K(d) = 0.04 microM vs. 2 microM). Mapping residue conservation, suppressor mutation sites, binding data, and deletion analysis onto the FliM(M) surface defines regions important for contacts with the stator-interacting protein FliG and for either counterclockwise or clockwise rotation. Association of 33-35 FliM subunits would generate a 44- to 45-nm-diameter disk, consistent with the known dimensions of the C-ring. The localization of counterclockwise- and clockwise-biasing mutations to distinct surfaces suggests that the binding of phosphorylated CheY cooperatively realigns FliM around the ring.

PubMed: 16882724
DOI: 10.1073/pnas.0602811103

実験手法

X-RAY DIFFRACTION (2 Å)