TY - JOUR
T1 - Solvent Entropy Contributions to Catalytic Activity in Designed and Optimized Kemp Eliminases
AU - Belsare, Saurabh
AU - Pattni, Viren
AU - Heyden, Matthias
AU - Head-Gordon, Teresa
N1 - Funding Information:
The hydration entropy analysis is supported by the Cluster of Excellence RESOLV (EXC 169) funded by the Deutsche Forschungsgemeinschaft (DFG), the RESOLV Graduate School “Solvation Science” (GSS), and UC Berkeley CalSolv center. T.H.G. also acknowledges support by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 for applications to catalysis.
Publisher Copyright:
© 2017 American Chemical Society.
PY - 2018/5/31
Y1 - 2018/5/31
N2 - We analyze the role of solvation for enzymatic catalysis in two distinct, artificially designed Kemp Eliminases, KE07 and KE70, and mutated variants that were optimized by laboratory directed evolution. Using a spatially resolved analysis of hydration patterns, intermolecular vibrations, and local solvent entropies, we identify distinct classes of hydration water and follow their changes upon substrate binding and transition state formation for the designed KE07 and KE70 enzymes and their evolved variants. We observe that differences in hydration of the enzymatic systems are concentrated in the active site and undergo significant changes during substrate recruitment. For KE07, directed evolution reduces variations in the hydration of the polar catalytic center upon substrate binding, preserving strong protein-water interactions, while the evolved enzyme variant of KE70 features a more hydrophobic reaction center for which the expulsion of low-entropy water molecules upon substrate binding is substantially enhanced. While our analysis indicates a system-dependent role of solvation for the substrate binding process, we identify more subtle changes in solvation for the transition state formation, which are less affected by directed evolution.
AB - We analyze the role of solvation for enzymatic catalysis in two distinct, artificially designed Kemp Eliminases, KE07 and KE70, and mutated variants that were optimized by laboratory directed evolution. Using a spatially resolved analysis of hydration patterns, intermolecular vibrations, and local solvent entropies, we identify distinct classes of hydration water and follow their changes upon substrate binding and transition state formation for the designed KE07 and KE70 enzymes and their evolved variants. We observe that differences in hydration of the enzymatic systems are concentrated in the active site and undergo significant changes during substrate recruitment. For KE07, directed evolution reduces variations in the hydration of the polar catalytic center upon substrate binding, preserving strong protein-water interactions, while the evolved enzyme variant of KE70 features a more hydrophobic reaction center for which the expulsion of low-entropy water molecules upon substrate binding is substantially enhanced. While our analysis indicates a system-dependent role of solvation for the substrate binding process, we identify more subtle changes in solvation for the transition state formation, which are less affected by directed evolution.
UR - http://www.scopus.com/inward/record.url?scp=85047996784&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85047996784&partnerID=8YFLogxK
U2 - 10.1021/acs.jpcb.7b07526
DO - 10.1021/acs.jpcb.7b07526
M3 - Article
C2 - 28899094
AN - SCOPUS:85047996784
SN - 1520-6106
VL - 122
SP - 5300
EP - 5307
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
IS - 21
ER -