The N-terminal region is crucial for the thermostability of the G-domain of Bacillus stearothermophilus EF-Tu.
Bacterial elongation factor Tu (EF-Tu) is a model monomeric G protein composed of three covalently linked domains. Previously, we evaluated the contributions of individual domains to the thermostability of EF-Tu from the thermophilic bacterium Bacillus stearothermophilus. We showed that domain 1 (G-domain) sets up the basal level of thermostability for the whole protein. Here we chose to locate the thermostability determinants distinguishing the thermophilic domain 1 from a mesophilic domain 1. By an approach of systematically swapping protein regions differing between G-domains from mesophilic Bacillus subtilis and thermophilic B. stearothermophilus, we demonstrate that a small portion of the protein, the N-terminal 12 amino acid residues, plays a key role in the thermostability of this domain. We suggest that the thermostabilizing effect of the N-terminal region could be mediated by stabilizing the functionally important effector region. Finally, we demonstrate that the effect of the N-terminal region is significant also for the thermostability of the full-length EF-Tu.
Laboratory of Molecular Genetics of Bacteria, Institute of Microbiology Academy of Sciences of the Czech Republic, Prague 142 20, Czech Republic.
Hana
H
Sanderová
Hana
H
Tiserová
Ivan
I
Barvík
Ludek
L
Sojka
Jirí
J
Jonák
Libor
L
Krásný
D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000235:genetics; D001411:Geobacillus stearothermophilus / Q000737:chemistry; D006358:Hot Temperature; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010444:Peptide Elongation Factor Tu / Q000737:chemistry* / Q000235:genetics; D055550:Protein Stability / Q000187:drug effects; D017434:Protein Structure, Tertiary / Q000235:genetics
D010444:Peptide Elongation Factor Tu