From signal perception to signal transduction: ligand‐induced dimeric switch of DctB sensory domain in solution Academic Article uri icon

abstract

  • Sinorhizobium meliloti DctB is a typical transmembrane sensory histidine kinase, which senses C(4)-dicarboxylic acids (DCA) and regulates the expression of DctA, the DCA transporter. We previously reported the crystal structures of its periplasmic sensory domain (DctBp) in apo and succinate-bound states, and these structures showed dramatic conformational changes at dimeric level. Here we show a ligand-induced dimeric switch in solution and a strong correlation between DctBp's dimerization states and the in vivo activities of DctB. Using site-directed mutagenesis, we identify important determinants for signal perception and transduction. Specifically, we show that the ligand-binding pocket is essential for DCA-induced 'on' activity of DctB. Mutations at different sections of DctBp's dimerization interface can lock full-length DctB at either 'on' or 'off' state, independent of ligand binding. Taken together, these results suggest that DctBp's signal perception and transduction occur through a 'ligand-induced dimeric switch', in which the changes in the dimeric conformations upon ligand binding are responsible for the signal transduction in DctB.

author list (cited authors)

  • Nan, B., Liu, X., Zhou, Y., Liu, J., Zhang, L. e., Wen, J., ... Wang, Y.

complete list of authors

  • Nan, Beiyan||Liu, Xin||Zhou, Yanfeng||Liu, Jiwei||Zhang, Le||Wen, Jin||Zhang, Xiaodong||Su, Xiao-Dong||Wang, Yi-Ping

publication date

  • January 1, 2010 11:11 AM

publisher