Attractant and repellent induce opposing changes in the four-helix bundle ligand-binding domain of a bacterial chemoreceptor

• DOI: 10.1371/journal.pbio.3002429
• Publication Date: 2023-12-11T18:34:54Z
• Authors: Lu Guo; Yun-Hao Wang; Rui Cui; Zhou Huang; Yuan Hong; Jia-Wei Qian; Bin Ni; An-Ming Xu; Cheng-Ying Jiang; Igor B. Zhulin; Shuang-Jiang Liu; De-Feng Li
• Keywords: Helix (gastropod)

Motile bacteria navigate toward favorable conditions and away from unfavorable environments using chemotaxis. Mechanisms of sensing attractants are well understood; however, molecular aspects how sense repellents have not been established. Here, we identified malate as a repellent recognized by the MCP2201 chemoreceptor in bacterium Comamonas testosteroni showed that it binds to same site an attractant citrate. Binding determinants for had only minor differences, single amino acid substitution binding inverted response attractant. We found citrate affect oligomerization state ligand-binding domain opposing way. also observed effects on orientation alpha helix connecting sensory transmembrane helix. propose model illustrate positive negative signals might be generated.