Research Summary:
The cheA gene in Escherichia coli encodes two proteins, a long form (CheAL) and short form (CheAS). CheAS is a truncated version of CheAL, where the first 98 amino acids of the N-terminal are lost due to an alternate translation start site in the cheA transcript. The missing N-terminal domain in CheAS contains the autophorylation site, His-48. The active CheA has been shown to exist as either a homodimer of CheAL, or in situ predominately as a heterodimer of CheAL and CheAS. CheAL acts as the functional histidine kinase that undergoes autophosphorylation, and then transfers this phosphate to CheY and/or CheB, whereas no definite function has been asigned to CheAS. It has been previously shown in our laboratory that CheAS interacts with CheZ, the phosphatase of CheY. The CheAS/CheZ interaction leads to enhanced dephosphorylation of CheY.
My research will further characterize the function of CheAS. Mutants of CheAS will be generated via site directed mutagenesis in order to study interactions of CheAS with CheZ, as well as other components of the chemotaxis signal transduction system. Structural data will be used to further characterize these mutants which should give insight into the function of CheAS.