Negative Epistasis and Evolvability in TEM-1 beta-Lactamase--The Thin Line between an Enzyme's Conformational Freedom and Disorder.
Dellus-Gur, E., Elias, M., Caselli, E., Prati, F., Salverda, M.L., de Visser, J.A., Fraser, J.S., Tawfik, D.S.(2015) J Mol Biol 427: 2396-2409
- PubMed: 26004540 
- DOI: 10.1016/j.jmb.2015.05.011
- Primary Citation of Related Structures:  
4OP5, 4OP8, 4OPQ, 4OPR, 4OPY, 4OPZ, 4OQ0, 4OQG, 4OQH, 4OQI - PubMed Abstract: 
Epistasis is a key factor in evolution since it determines which combinations of mutations provide adaptive solutions and which mutational pathways toward these solutions are accessible by natural selection. There is growing evidence for the pervasiveness of sign epistasis--a complete reversion of mutational effects, particularly in protein evolution--yet its molecular basis remains poorly understood ...