1H, 13C and 15N resonance assignments for the response regulator CheY3 from Rhodobacter sphaeroides

Rhodobacter sphaeroides has emerged as a model system for studies of the complex chemotaxis pathways that are a hallmark of non-enteric bacteria. The genome of R. sphaeroides encodes two sets of flagellar genes, fla1 and fla2, that are controlled by three different operons. Each operon encodes homologues of most of the proteins required for the well-studied E. coli chemotaxis pathway. R. sphaeroides has six homologues of the response regulator CheY that are localized to and are regulated by different clusters of chemosensory proteins in the cell and have different effects on chemotaxis. CheY6 is the major CheY stopping the fla1 flagellar motor. CheY3 and CheY4, which are associated with the polar cluster, can bind to but not stop the motor, but one or the other of these is required for chemotaxis. We are using NMR spectroscopy to characterise the structure and dynamics of CheY3 and CheY6 in solution. We are interested in defining the conformational changes that occur upon activation of these two proteins and to identify differences in their properties that can explain the different functions they play in chemotaxis in R. sphaeroides. Here we present the 1H, 13C and 15N assignments for CheY3 in its active, inactive and Mg2+-free apo form. These assignments provide the starting point for detailed investigations of the structure and function of CheY3