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Combining multi-mutant and modular thermodynamic cycles to measure energetic coupling networks in enzyme catalysis.
- Source :
-
Structural dynamics (Melville, N.Y.) [Struct Dyn] 2017 Jan 26; Vol. 4 (3), pp. 032101. Date of Electronic Publication: 2017 Jan 26 (Print Publication: 2017). - Publication Year :
- 2017
-
Abstract
- We measured and cross-validated the energetics of networks in Bacillus stearothermophilus Tryptophanyl-tRNA synthetase (TrpRS) using both multi-mutant and modular thermodynamic cycles. Multi-dimensional combinatorial mutagenesis showed that four side chains from this "molecular switch" move coordinately with the active-site Mg <superscript>2+</superscript> ion as the active site preorganizes to stabilize the transition state for amino acid activation. A modular thermodynamic cycle consisting of full-length TrpRS, its Urzyme, and the Urzyme plus each of the two domains deleted in the Urzyme gives similar energetics. These dynamic linkages, although unlikely to stabilize the transition-state directly, consign the active-site preorganization to domain motion, assuring coupled vectorial behavior.
Details
- Language :
- English
- ISSN :
- 2329-7778
- Volume :
- 4
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- Structural dynamics (Melville, N.Y.)
- Publication Type :
- Academic Journal
- Accession number :
- 28191480
- Full Text :
- https://doi.org/10.1063/1.4974218