Cooperative phenomena in the photocycle of D96N mutant bacteriorhodopsin

Stationary Phase EPR Spectroscopy for Monitoring Membrane Protein Refolding by Conformational Response

“…There exists only one 2.5 Å-resolution crystal structure of HmbRI, and its structural dynamics are largely unstudied. HsbR is known to have conformationally distinct intermediates in its photocycle, ,, most notably the spectroscopically distinct M-intermediate, whose decay can be drastically slowed by the implementation of the D96N mutation. , The reported photochemical characteristics of HmbRI D94N are similar in this respect. Moreover, the M-intermediate decay can be further slowed by increasing the pH to 8. , Thus, the EPR spectral lineshape of spin-labeled HmbRI bound to Ni-NTA agarose resin is expected to vary between the dark and light states, and the degree of the lineshape variance is proportional to the quantity of HmbRI correctly refolded on the resin.…”