Details

Autor(en) / Beteiligte

• Hong, Yuan
• Huang, Zhou
• Guo, Lu
• Ni, Bin
• Jiang, Cheng‐Ying
• Li, Xiao‐Jing
• Hou, Yan‐Jie
• Yang, Wen‐Si
• Wang, Da‐Cheng
• Zhulin, Igor B.
• Liu, Shuang‐Jiang
• Li, De‐Feng

Titel

The ligand‐binding domain of a chemoreceptor from Comamonas testosteroni has a previously unknown homotrimeric structure

Ist Teil von

• Molecular microbiology, 2019-09, Vol.112 (3), p.906-917

Ort / Verlag

England: Blackwell Publishing Ltd

Erscheinungsjahr

2019

Link zum Volltext

Quelle

Wiley Online Library - AutoHoldings Journals

Beschreibungen/Notizen

• Summary 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. The structure of chemoreceptor MCP2201 LBD was solved. The apo‐form (ligand‐free) of MCP2201 LBD is a 4HB homodimer. In the presence of ligand citric acid, a previously unknown trimeric structure of MCP2201 LBD was observed. These results raised the possibility that ligand‐binding induced oligomer‐organization dynamics and subsequently signal generation within chemoreceptors.