Explanation of the stability of thermophilic proteins based on unique micromorphology.
Two mesophilic/thermophilic variants of the G-domain of the elongation factor Tu were studied via molecular dynamics simulations. By analyzing the simulation data via the Voronoi space tessellation, we have found that the two proteins have the same macromolecular packing, while the water-exposed surface area is larger for the thermophile. A larger coordination with water is probably due to a peculiar corrugation of the exposed surface of this species. From an enthalpic point of view, the thermophile shows a larger number of intramolecular hydrogen bonds, stronger electrostatic interactions, and a flatter free-energy landscape. Overall, the data suggest that the specific hydration state enhances macromolecular fluctuations but, at the same time, increases thermal stability.
Melchionna
Simone
S
Istituto Nazionale di Fisica della Materia-SOFT, Department of Physics, Università di Roma La Sapienza, Rome, Italy. simone.melchionna@roma1.infn.it
Sinibaldi
Raffaele
R
Briganti
Giuseppe
G
D001426:Bacterial Proteins / Q000737:chemistry*; D001665:Binding Sites; D003198:Computer Simulation; D004926:Escherichia coli / Q000378:metabolism; D006860:Hydrogen Bonding; D008958:Models, Molecular; D010444:Peptide Elongation Factor Tu / Q000737:chemistry*; D013816:Thermodynamics; D016963:Thermus thermophilus / Q000378:metabolism; D014867:Water / Q000737:chemistry
D001426:Bacterial Proteins; D014867:Water; D010444:Peptide Elongation Factor Tu