@article {1109,
	title = {Rapid Thermal Tuning of Chromophore Structure in Membrane Protein},
	journal = {Journal of Physical Chemistry B},
	volume = {113},
	number = {13},
	year = {2009},
	note = {Wang, Jianping El-Sayed, Mostafa A.},
	month = {Apr},
	pages = {4184-4186},
	abstract = {We show that the configuration and the optical property of the retinal chromophore in bacteriorhodopsin (bR) can be tuned dynamically from the all-trans configuration to the 13-cis by using a nanosecond laser-induced temperature-jump. The rapid bleach in the visible absorption optical density of retinal has an apparent formation time of ca. 170 ns, whereas the relaxation process finishes within tens of ms. The dynamical transition of retinal from the all-trans to 13-cis species is believed to occur as a result of rapid protein conformational change especially in the vicinity of retinal binding site. Our study reveals the intrinsic dynamical aspect of the retinal chromophore with respect to the protein structure.},
	isbn = {1520-6106},
	doi = {10.1021/jp901560m},
	author = {Wang, Jianping and El-Sayed, Mostafa A}
}
@article {1192,
	title = {Refolding of thermally denatured bacteriorhodopsin in purple membrane},
	journal = {Journal of Physical Chemistry B},
	volume = {106},
	number = {3},
	year = {2002},
	note = {Wang, JP Heyes, CD El-Sayed, MA},
	month = {Jan},
	pages = {723-729},
	abstract = {The change in protein conformational structure and retinal chromophore binding state have been examined by using in situ UV-vis, FTIR, and CD spectroscopies during the thermal denaturation and refolding processes in bacteriorhodopsin (bR) of purple membrane (PM), in its native trimeric and in Triton X-100 solubilized monomeric form. For the trimeric bR, it is found that heating bR through its premelting transition (T > 78 degreesC, T-m{\textquoteright}) does not cause any permanent damage in the protein secondary structure, and a reversible refolding occurs when it cools back to room temperature. For the monomeric bR, it is found that it is less thermally stable than the trimer. There is a significant change in its protein secondary structure and a complete dissociation of retinal occurs irreversibly at a temperature as low as 66 degreesC. In addition, it is found that heating the trimeric bR through its main molten state (T > 96 degreesC, T-m) changes the protein secondary structure so that bR does not refold fully into its original secondary structure. Upon cooling back to room temperature, about 90\% of the bound retinal in native bR recovers after being heated through its premelting transition, whereas only about 12\% of bound retinal recovers if bR is heated above its main melting temperature. It is also found that refolded bR molecules with their retinal chromophore rebound have a photocycle and are capable of pumping protons. Our results also suggest that from its molten state, protein secondary structure refolding precedes retinal rebinding to the Schiff base.},
	isbn = {1520-6106},
	doi = {10.1021/jp013131a},
	author = {Wang, Jianping and Heyes, C D and El-Sayed, Mostafa A}
}
