AI Article Synopsis
- Flexible protein sequences change quickly between different states, which makes it challenging to determine how these variations affect their function experimentally.
- Researchers utilized carbon-deuterium bond vibrations as infrared probes to study the diverse states of proline-rich sequences and their role in interacting with Src homology 3 domains.
- The findings revealed multiple sub-populations at proline residues, showing that the binding interaction often follows a conformational selection mechanism, where adaptability among these states affects recognition specificity and binding entropy.
Article Abstract
Flexible protein sequences populate ensembles of rapidly interconverting states differentiated by small-scale fluctuations; however, elucidating whether and how the ensembles determine function experimentally is challenged by the combined high spatial and temporal resolution needed to capture the states. We used carbon-deuterium (C-D) bond vibrations incorporated as infrared probes to characterize with residue-specific detail the heterogeneity of states adopted by proline-rich (PR) sequences and assess their involvement in recognition of Src homology 3 domains. The C-D absorption envelopes provided evidence for two or three sub-populations at all proline residues. The changes in the subpopulations induced by binding generally reflected recognition by conformational selection but depended on the residue and the state of the ligand to illuminate distinct mechanisms among the PR ligands. Notably, the spectral data indicate that greater adaptability among the states is associated with reduced recognition specificity and that perturbation to the ensemble populations contributes to differences in binding entropy. Broadly, the study quantifies rapidly interconverting ensembles with residue-specific detail and implicates them in function.
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| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8066399 | PMC |
| http://dx.doi.org/10.1021/acs.jpcb.9b07036 | DOI Listing |
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