Section: New Results

Applications

Methods and tools developed in our group have been used in the following studies:

Building Blocks of Bacterial Chemoreceptor Arrays

Participant : Sergei Grudinin.

Bacterial chemoreceptors are known to cluster at the cell poles where they form partially hexagonally ordered arrays. This clusterisation is important for the function of chemotaxis system. In this study, we performed an analysis of the known structural and biochemical information on the components of chemoreceptor arrays: chemoreceptors themselves, histidine kinases and adapter proteins. Based on this analysis, we proposed a set of basic interactions within the chemotaxis system(the array building blocks) and constructed their atomistic models. The models resulting from these blocks are in agreement with experimental information and provide a basis for understanding the atomic-level structural organization of chemoreceptor arrays.

A Novel Dimerization Interface of Cyclic Nucleotide Binding Domain

Participant : Sergei Grudinin.

Cyclic nucleotide binding domain (CNBD) is a ubiquitous domain of effector proteins involved in signalling cascades of prokaryota and eukaryota. In this study, we described a novel CNBD dimerization interface found in crystal structures of bacterial CNG channel MlotiK1 and mammalian second messenger cAMP-activated guanine nucleotide-exchange factor Epac2. Using computational tools we demonstrated that the found interface is stable, in contrast to the dimerization interface reported previously. Comparisons with cN-bound structures of CNBD showed that the dimerization is incompatible with second messenger cAMP binding. Thus, the cAMP-dependent monomerization of CNBD may be an alternative mechanism of the cAMP sensing. Based on these findings, we proposed a model of the bacterial CNG channel modulation by cAMP.