1. Intrinsic Dynamics of Protein-Peptide Unbinding.
- Author
-
Jankovic B, Bozovic O, and Hamm P
- Subjects
- Kinetics, Peptides chemistry, Proteins chemistry, Proteins metabolism, Ribonucleases physiology, Ribonucleases ultrastructure, Spectrometry, Fluorescence instrumentation, Spectrometry, Fluorescence methods, Peptides metabolism, Protein Binding physiology, Ribonucleases metabolism
- Abstract
The dynamics of peptide-protein binding and unbinding of a variant of the RNase S system has been investigated. To initiate the process, a photoswitchable azobenzene moiety has been covalently linked to the S-peptide, thereby switching its binding affinity to the S-protein. Transient fluorescence quenching was measured with the help of a time-resolved fluorometer, which has been specifically designed for these experiments and is based on inexpensive light-emitting diodes and laser diodes only. One mutant shows on-off behavior with no specific binding detectable in one of the states of the photoswitch. Unbinding is faster by at least 2 orders of magnitude, compared to that of other variants of the RNase S system. We conclude that unbinding is essentially barrier-less in that case, revealing the intrinsic dynamics of the unbinding event, which occurs on a time scale of a few hundred microseconds in a strongly stretched-exponential manner.
- Published
- 2021
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