Abstract
We identified and characterized a new Escherichia coli gene, htrP. The htrP gene was identified because its insertional inactivation by the Tn10 transposon results in the inability of E. coli to form colonies at temperatures above 37 degrees C and a slow growth phenotype at 30 degrees C. The htrP gene was cloned and mapped to 66.3 min on the E. coli genetic map, 4 kbp clockwise from the tolC gene. The htrP gene was sequenced and shown to code for an acidic, 27,471-Da polypeptide and to be transcribed counterclockwise with respect to the genetic map. The predicted HtrP protein has two potential transmembrane segments and shares an identity of 64.4% over a length of 210 amino acids with the LuxH protein. Despite the fact that the htrP gene is essential for E. coli growth exclusively at high temperatures, the levels of htrP-specific transcripts decrease with increasing temperature.