Survival of microorganisms depends on their ability to sense and respond to environmental changes. Motile bacteria can sense chemical gradients and control directed motility in chemical gradients in a process that utilizes methyl accepting
chemotaxis proteins. The chemotaxis system of E. coli is composed of two major (Tar and Tsr) and three minor (Tap, Trg, Aer) chemoreceptors. The basic structure of a chemoreceptor consists of three main parts, the periplasmic ligand-binding domain (not present in Aer), the transmembrane domain and the cytoplasmic domain. The receptors cluster in hexagonal structures of trimers of dimers predominantly at the cell poles. During logarithmic growth phase, the cytoplasmic membrane of E. coli contains approximately 75% phosphatidylethanolamin, 20% phosphatidylglycerol and 5% cardiolipin (CL). CL is enriched in nucleoid free regions of the membrane, at the cell poles and the cell septum.
In our study we are investigating in the influence of cardiolipin on the chemotaxis system of E. coli. Our preliminary data shows, that the absence of CL influences bacterial growth at the stationary phase, the chemoreceptor clustering and chemosensing towards certain attractants.