Screening of a Thermus thermophilus genomic library led to the identificati
on of a homologue of the ylmE gene. ylmE is highly conserved in widely dive
rgent organisms from prokaryotes to mammals, suggesting an important, albei
t currently unknown, cellular function. The 633 bp gene has a GC content of
69.2% overall and 90% in the third nucleotide position, while the gene pro
duct is predicted to be a soluble cytoplasmic protein of 23441 Da. It belon
gs to a family of conserved proteins of unknown function and exhibits amino
acid identities ranging from 45% to 28% to the Aquifex aeolicus and Saccha
romyces cerevisiae family members, respectively. We speculate that the gene
product may be involved in a cellular stress response in T. thermophilus.