We propose a dual-scale approach to predict the native structures of retinal proteins (RPs) by combining coarse-grained (CG) Monte-Carlo simulations and all-atom (AA) molecular dynamics simulations to pack their transmembrane helices correctly. This approach has been applied to obtain the structures of five RPs, including bacteriorhodopsin (BR), halorhodopsin (HR), sensory rhodopsin I (SRI), se...

Microorganisms show attractant and repellent responses to survive in the various environments in which they live. Those phototaxic (to light) and chemotaxic (to chemicals) responses are regulated by membrane-embedded receptors and transducers. This article reviews the following: (1) the signal relay mechanisms by two photoreceptors, Sensory Rhodopsin I (SRI) and Sensory Rhodopsin II (SRII) and ...

The semi-classical theory of collisional depolarization of spectral lines of neutral atoms by atomic hydrogen (Derouich et al. 2003a; Derouich et al. 2003b; Derouich et al. 2004 and references therein) is extended to spectral lines of singly ionised atoms. In this paper we apply our general method to the particular cases of the 3d D and 4p P states of the CaII ion and to the 5p P state of the S...

The two transducers in the phototaxis system of the archaeon Halobacterium salinarum, HtrI and HtrII, are methyl-accepting proteins homologous to the chemotaxis transducers in eubacteria. Consensus sequences predict three glutamate pairs containing potential methylation sites in HtrI and one in HtrII. Mutagenic substitution of an alanine pair for one of these, Glu265-Glu266, in HtrI and for the...

Photoactivation of attractant phototaxis receptor sensory rhodopsin I (SRI) in Halobacterium salinarum entails transfer of a proton from the retinylidene chromophore's Schiff base (SB) to an unidentified acceptor residue on the cytoplasmic half-channel, in sharp contrast to other microbial rhodopsins, including the closely related repellent phototaxis receptor SRII and the outward proton pump b...

We investigated in meso crystallization of membrane proteins to develop a fast screening technology which combines features of the well established classical vapor diffusion experiment with the batch meso phase crystallization, but without premixing of protein and monoolein. It inherits the advantages of both methods, namely (i) the stabilization of membrane proteins in the meso phase, (ii) the...