The Gating mechanism in the bacterial mechanosensitive channel MscL

The discovery and molecular identification of the large-conductance mechanosensitive channel MscL is presented in this short review. Not only the 3D crystal structure of a MscL homolog, but some information on the gating transition are currently available. The progress in the field has resulted from successful "brut force attacks" at some stages, but also included the element of serendipity. Combined efforts of several research groups permitted to avoid misinterpretations that could be drawn from the data obtained with a single method, and finally to supplement the partial crystal structure with missing details. The structural model of the gating mechanism implies a large-scale conformational transition in the protein complex that involves sequential opening of two separate gates. Many of the modeling predictions have been confirmed experimentally. MscL is a system that allows us to find answers to a number of fundamental questions on the structure and dynamics of membrane proteins and the primary mechanisms of mechanosensation.