Bai F, Branch RW, Nicolau DV, Pilizota T, Steel BC, Maini PK, Berry RM
Conformational spread as a mechanism for cooperativity in the bacterial flagellar switch.
Science. 2010 Feb 5;327(5966):685-9
Authors: Bai F, Branch RW, Nicolau DV, Pilizota T, Steel BC, Maini PK, Berry RM
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.
PMID: 20133571 [PubMed - indexed for MEDLINE]