Stability parameters for individual residues in Thermus thermophilus cysteine-free RNase H were determined by native state hydrogen exchange, thus providing a unique comparison of regional thermodynamics between thermophilic and mesophilic homologues. The general distribution of stability in the thermophilic protein is similar to that of its mesophilic homologue, with a proportional increase in stability for almost all residues. As a consequence, the residue-specific stabilities of the two proteins are remarkably similar under conditions where their global stabilities are the same. These results indicate that T. thermophilus RNase H is stabilized in a delocalized fashion, preserving a finely tuned balance of stabilizing interactions throughout the structure. Therefore, although protein stability can be altered by single amino acid substitution, evolution for optimal function may require more subtle and delocalized mechanisms. Study holds ProTherm entries: 6450, 6451, 6452, 6453, 6454, 6455, 6456, 6457, 6458, 6459, 6460, 6461, 6462, 6463, 6464, 6465, 6466, 6467, 6468, 6469, 6470, 6471, 6472, 6473, 6474, 6475, 6476, 6477, 6478, 6479, 6480, 6481, 6482, 6483, 6484, 6485, 6486, 6487, 6488 Extra Details: stability parameters of native state hydrogen exchange at A10 stability parameter; thermophilic; mesophilic;,residue-specific stability; delocalized mechanism
Submitter: Connie Wang
Submission Date: April 24, 2018, 8:32 p.m.
|Number of data points||78|
|Proteins||Ribonuclease H ; Ribonuclease H|
|Assays/Quantities/Protocols||Experimental Assay: m ; Experimental Assay: dG_H2O|
|Libraries||Mutations for sequence MNPSPRKRVALFTDGACLGNPGPGGWAALLRFHAHEKLLSGGEACTTNNRMELKAAIEGLKALKEPCEVDLYTDSHYLKKAFTEGWLEGWRKRGWRTAEGKPVKNRDLWEALLLAMAPHRVRFHFVKGHTGHPENERVDREARRQAQSQAKTPCPPRAPTLFHEEA|