Edinburgh Research Explorer

Conformational Spread as a Mechanism for Cooperativity in the Bacterial Flagellar Switch

Research output: Contribution to journalArticle

  • Fan Bai
  • Richard W. Branch
  • Dan V. Nicolau
  • Teuta Pilizota
  • Bradley C. Steel
  • Philip K. Maini
  • Richard M. Berry

Related Edinburgh Organisations

Original languageEnglish
Pages (from-to)685-689
Number of pages5
Issue number5966
Publication statusPublished - 5 Feb 2010


The bacterial flagellar switch that controls the direction of flagellar rotation during chemotaxis has a highly cooperative response. This has previously been understood in terms of the classic two-state, concerted model of allosteric regulation. Here, we used high-resolution optical microscopy to observe switching of single motors and uncover the stochastic multistate nature of the switch. Our observations are in detailed quantitative agreement with a recent general model of allosteric cooperativity that exhibits conformational spread-the stochastic growth and shrinkage of domains of adjacent subunits sharing a particular conformational state. We expect that conformational spread will be important in explaining cooperativity in other large signaling complexes.

ID: 5841488