Cloning and characterization of the hrpA gene in the terC region of Escherichia coil that is highly similar to the DEAH family RNA helicase genes of Saccharomyces cerevisiae

During the course of systematic nucleotide sequence analysis of the terC region of E.coli K-12 by using the ordered lambda phage clones, we found the presence of a gene, termed hrpA, that showed a high degree of sequence similarity to the PRP2, PRP16 and PRP22 genes of Sacchammyces cerevisiae. The products of these yeast genes are known to play their roles in mRNA splicing, and belong to a group of proteins collectively called the DEAH family. The hrpA gene is the first example of a DEAH family gene in prokaryotes. The N-terminal region of the protein it encodes contains conserved sequence stretches characteristic of an RNA helicase. its molecular mass is caicuiated to be 146 kDa. Previously, a 135 kDa protein was identified by Moir et aL [J Bacterlol. (1992) 174, 21 02-2110] in this region which is most likely identical to that encoded by hrpA. The C-terminal region of the hrpA gene product seems to contain an RNA binding motif weakly resembiing that of ribosomal protein S1 of E.coli Disruption of the hrpA gene suggested that It is not essential for the growth of E.coli