Side-chain carboxyl and carbonyl groups play a major role in protein interactions and enzyme catalysis. A series of C-13 relaxation experiments is introduced to study the dynamics of carboxyl and carbonyl groups in protein side chains on both fast (sub-ns) and slower (mu s-ms) time scales. This approach is illustrated on the protein calbindin D-9k. Fast dynamics features correlate with hydrogen- and ion-binding patterns. We also identify chemical dynamics on mu s time scales in solvent-exposed carboxyl groups, most probably due to exchange between the carboxylate and carboxylic acid forms.
David Lyndon Emsley, Pierrick Berruyer, Andrea Bertarello, Baptiste Busi
Jérôme Waser, Christian Heinis, Gontran Sangouard, Elija Grinhagena
David Lyndon Emsley, Marinella Mazzanti, Anne-Sophie Chauvin, Dominik Józef Kubicki, Gabriele Stevanato, Georges Guévork Jean-Jacques Menzildjian