6ITS

The citrate-bound trimer of chemoreceptor MCP2201 ligand binding domain

Summary for 6ITS

• Entry DOI: 10.2210/pdb6its/pdb
• Related: 5XUA 5XUB
• Descriptor: Methyl-accepting chemotaxis sensory transducer, CITRIC ACID (3 entities in total)
• Functional Keywords: methyl-accepting chemotaxis protein, four helix bundle, dicarboxylic organic acid binding, signaling protein
• Biological source: Comamonas testosteroni (strain CNB-2)
• Total number of polymer chains: 2
• Total formula weight: 36661.38

Authors

Hong, Y.,Li, D.F. (deposition date: 2018-11-26, release date: 2018-12-26, Last modification date: 2023-11-22)

Primary citation

Hong, Y.,Huang, Z.,Guo, L.,Ni, B.,Jiang, C.Y.,Li, X.J.,Hou, Y.J.,Yang, W.S.,Wang, D.C.,Zhulin, I.B.,Liu, S.J.,Li, D.F.
The ligand-binding domain of a chemoreceptor from Comamonas testosteroni has a previously unknown homotrimeric structure.
Mol.Microbiol., 112:906-917, 2019

PubMed Abstract: Transmembrane chemoreceptors are widely present in Bacteria and Archaea. They play a critical role in sensing various signals outside and transmitting to the cell interior. Here, we report the structure of the periplasmic ligand-binding domain (LBD) of the transmembrane chemoreceptor MCP2201, which governs chemotaxis to citrate and other organic compounds in Comamonas testosteroni. The apo-form LBD crystal revealed a typical four-helix bundle homodimer, similar to previously well-studied chemoreceptors such as Tar and Tsr of Escherichia coli. However, the citrate-bound LBD revealed a four-helix bundle homotrimer that had not been observed in bacterial chemoreceptor LBDs. This homotrimer was further confirmed with size-exclusion chromatography, analytical ultracentrifugation and cross-linking experiments. The physiological importance of the homotrimer for chemotaxis was demonstrated with site-directed mutations of key amino acid residues in C. testosteroni mutants.

PubMed: 31177588
DOI: 10.1111/mmi.14326

Experimental method

X-RAY DIFFRACTION (2.501 Å)