Characterization of novel chemotaxis proteins in Bacillus subtilis

Chemotactic bacteria including Bacillus subtilis migrate towards more favorable conditions by using a signalling system that controls the direction of rotation of the flagella. Many proteins involved in this system show widespread similarity, but several unique chemotactic genes have been identified in B. subtilis that could account for the differences in behavior and biochemistry of this organism from other chemotactic bacteria.One of these genes, cheD, encodes a protein that is required by the methyltransferase to methylate many of the chemoreceptors (or methyl-accepting chemotaxis proteins), probably by structural modification of the receptors upon binding. Another unique protein, CheC, is shown to associate with CheD, and is involved in downregulating methyltransferase activity, possibly as part of the feedback of the behavior of the bacterial cell. It is thought that these two proteins are bound to the receptors and together regulate methylation and consequently affect chemotactic behavior.CheV is another novel protein thought to be bound at the receptors. It has regions homologous to CheW (N-terminus) and CheY (C-terminus) and exhibits functional redundancy with CheW, the coupler between the autophosphorylating kinase and the receptors.There are indications for the identity of an acceptor that receives methyl groups from the receptors. Moreover, DNA fragments possibly encoding additional chemoreceptors have been identified.U of I OnlyETDs are only available to UIUC Users without author permissio