FTIR Spectroscopy of the M Photointermediate in pharaonis Phoborhodopsin

Role of Asp193 in chromophore-protein interaction of pharaonis phoborhodopsin (sensory rhodopsin II).

Pharaonis phoborhodopsin (ppR; also pharaonis sensory rhodopsin II, psRII) is a receptor of the negative phototaxis of Natronobacterium pharaonis. By spectroscopic titration of D193N and D193E mutants, the pK(a) of the Schiff base was evaluated. Asp193 corresponds to Glu204 of bacteriorhodopsin (bR). The pK(a) of the Schiff base (SBH(+)) of D193N was approximately 10.1-10.0 (at XH(+)) and appro...

Selective Reaction of Hydroxylamine with Chromophore during Photocycle of pharaonis Phoborhodopsin by

Phoborhodopsin (pR; also called sensory rhodopsin II, sRII) is a receptor of negative phototaxis of Halobacterium salinarum, and pharaonis phoborhodopsin (ppR; also pharaonis sensory rhodopsin II, psRII) is a corresponding protein of Natronobacterium pharaonis. These receptors contain retinal as a chromophore which bind to a lysine residue via Schiff base. This Schiff base can be cleaved with h...

Evaluating the Role of antioxidants in the stabilization of hydroxypropyl cellulose by ATR-FTIR Spectroscopy

This study is aimed at evaluating the performance of tetrakismethylene-3-3,5-di-tert-butyl-4-hydroxyphenyl propionate methane S1010, tris2,4-di-tert-butylphenyl phosphite S1680 and ascorbic acid AA antioxidants in stabilization of hydroxypropyl cellulose HPC. For this purpose, a number of films with weight percent ratios of 0.4 w/w were prepared in a 1 isopropanol solution w/v. Then, the films ...

An active photoreceptor intermediate revealed by in situ photoirradiated solid-state NMR spectroscopy.

A novel, to our knowledge, in situ photoirradiation system for solid-state NMR measurements is improved and demonstrated to successfully identify the M-photointermediate of pharaonis phoborhodopsin (ppR or sensory rhodopsin II), that of the complex with transducer (ppR/pHtrII), and T204A mutant embedded in a model membrane. The (13)C NMR signals from [20-(13)C]retinal-ppR and ppR/pHtrII reveale...

ftir spectroscopy in biological research