Quantifying a light-induced energetic change in bacteriorhodopsin by force spectroscopy.

ABSTRACT: Ligand-induced conformational changes are critical to the function of many membrane proteins and arise from numerous intramolecular interactions. In the photocycle of the model membrane protein bacteriorhodopsin (bR), absorption of a photon by retinal triggers a conformational cascade that results in pumping a proton across the cell membrane. While decades of spectroscopy and structural studies have probed this photocycle in intricate detail, changes in intramolecular energetics that underlie protein motions have remained elusive to experimental quantification. Here, we measured these energetics on the millisecond time scale using atomic-force-microscopy-based single-molecule force spectroscopy. Precisely, timed light pulses triggered the bR photocycle while we measured the equilibrium unf

SUBMITTER: Jacobson DR 

PROVIDER: S-EPMC10873598 | biostudies-literature | 2024 Feb

REPOSITORIES: biostudies-literature