The catalytic subunit of cAMP-dependent protein kinase A (PKA-C) is an exquisite example of a single molecule allosteric enzyme, where classical and modern views of allosteric signaling merge. In this chapter, we describe the mapping of PKA-C conformational dynamics and allosteric signaling in the free and bound states using a combination of NMR spectroscopy and molecular dynamics simulations. We show that ligand binding affects the enzyme's conformational dynamics, shaping the free-energy landscape toward the next stage of the catalytic cycle. While nucleotide and substrate binding enhance the enzyme's conformational entropy and define dynamically committed states, inhibitor binding attenuates the internal dynamics in favor of enthalpic interactions and delineates dynamically quenched states. These studies support a central role of conformational dynamics in many aspects of enzymatic turnover and suggest future avenues for controlling enzymatic function.
|Original language||English (US)|
|Title of host publication||Advances in Protein Chemistry and Structural Biology|
|Publisher||Academic Press Inc.|
|Number of pages||27|
|State||Published - 2012|
|Name||Advances in Protein Chemistry and Structural Biology|
Bibliographical noteFunding Information:
This work was supported by the NIH grants GM72701 and GM 100310 to G. V. and T32DE007288 to L. R. M. NMR data were collected at NMRFAM (NIH: P41RR02301, P41GM66326, RR02781, and RR08438; NSF: DMB-8415048, OIA-9977486, BIR-9214394) and the U. of Minnesota NMR Facility (NSF BIR-961477). Modeling and calculations were carried out at the Minnesota Supercomputing Institute.
Copyright 2019 Elsevier B.V., All rights reserved.
- Extended conformational selection
- Protein kinase A
- Substrate recognition