Adaptation to extreme environments: macromolecular dynamics in bacteria compared in vivo by neutron scattering.
Mean macromolecular dynamics was quantified in vivo by neutron scattering in psychrophile, mesophile, thermophile and hyperthermophile bacteria. Root mean square atomic fluctuation amplitudes determining macromolecular flexibility were found to be similar for each organism at its physiological temperature ( approximately 1 A in the 0.1 ns timescale). Effective force constants determining the mean macromolecular resilience were found to increase with physiological temperature from 0.2 N/m for the psychrophiles, which grow at 4 degrees C, to 0.6 N/m for the hyperthermophiles (85 degrees C), indicating that the increase in stabilization free energy is dominated by enthalpic rather than entropic terms. Larger resilience allows macromolecular stability at high temperatures, while maintaining flexibility within acceptable limits for biological activity.
Tehei
Moeava
M
Institut de Biologie Structurale, CEA-CNRS-UJF, IBS, 41 rue Jules Horowitz, 38027 Grenoble Cedex 1, France.
Franzetti
Bruno
B
Madern
Dominique
D
Ginzburg
Margaret
M
Ginzburg
Ben Z
BZ
Giudici-Orticoni
Marie-Thérèse
MT
Bruschi
Mireille
M
Zaccai
Giuseppe
G
D000223:Adaptation, Psychological; D001419:Bacteria / Q000737:chemistry*; D004926:Escherichia coli / Q000737:chemistry; D046911:Macromolecular Substances; D015233:Models, Statistical; D009502:Neutrons; D042802:Oxalobacteraceae / Q000737:chemistry / Q000145:classification; D011513:Proteus mirabilis / Q000737:chemistry; D012542:Scattering, Radiation; D013696:Temperature; D013816:Thermodynamics; D016963:Thermus thermophilus / Q000737:chemistry
D046911:Macromolecular Substances