Elongation factor Tu of the extreme thermophilic hydrogen oxidizing bacterium calderobacterium hydrogenophilum

Protein synthesis elongation factor Tu has been purified from an extreme thermophilic hydrogen oxidizing bacterium Calderobacterium hydrogenophilum. The molecular mass of EF-Tu .GDP is 51 000. The factor is heat stable and loses only 50 % of its activity after heating for 5 min at 80°C. Under mild conditions trypsin cleaved EF-Tu.GDP to four main fragments. Only one fragment of M r = 20 000 had a mobility similar to the trypsin fragment “B” of Escherichia coli EF-Tu. Other peptide fragments of E. coli and C. hydrogenophilum EF-Tu differed in size, but native preparations of both factors are immunologically similar.