Weakened coupling of conserved arginine to the proteorhodopsin chromophore and its counterion implies structural differences from bacteriorhodopsin

Partha, Ranga; Krebs, R.; Caterino, Tamara L.; Braiman, Mark S.

doi:10.1016/j.bbabio.2004.12.009

Cited by 25 publications

(33 citation statements)

References 43 publications

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“…This sug gests that in the ESR molecule, in contrast to BR [36,37], the Arg82 residue is weakly bound to the proton acceptor from the Schiff base. A similar situation was observed for PR [38]. In contrast, replacement of His57 with a methionine residue (H57M) leads to substantial change in properties of the acceptor complex.…”

Section: Role Of His57 Residue In Modulating Pk a Of Proton Acceptor supporting

confidence: 62%

ESR — A retinal protein with unusual properties from Exiguobacterium sibiricum

Petrovskaya

Balashov

Лукашев

et al. 2015

Biochemistry Moscow

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This review covers the properties of a retinal protein (ESR) from the psychrotrophic bacterium Exiguobacterium sibiricum that functions as a light-driven proton pump. The presence of a lysine residue at the position corresponding to intramolecular proton donor for the Schiff base represents a unique structural feature of ESR. We have shown that Lys96 successfully facilitates delivery of protons from the cytoplasmic surface to the Schiff base, thus acting as a proton donor in ESR. Since proton uptake during the photocycle precedes Schiff base reprotonation, we conclude that this residue is initially in the uncharged state and acquires a proton for a short time after Schiff base deprotonation and M intermediate formation. Involvement of Lys as a proton donor distinguishes ESR from the related retinal proteins - bacteriorhodopsin (BR), proteorhodopsin (PR), and xanthorhodopsin (XR), in which the donor function is performed by residues with a carboxyl side chain. Like other eubacterial proton pumps (PR and XR), ESR contains a histidine residue interacting with the proton acceptor Asp85. In contrast to PR, this interaction leads to shift of the acceptor's pKa to more acidic pH, thus providing its ability to function over a wide pH range. The presence of a strong H-bond between Asp85 and His57, the structure of the proton-conducting pathways from cytoplasmic surface to the Schiff base and to extracellular surface, and other properties of ESR were demonstrated by solving its three-dimensional structure, which revealed several differences from known structures of BR and XR. The structure of ESR, its photocycle, and proton transfer reactions are discussed in comparison with homologous retinal proteins.

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Section: Role Of His57 Residue In Modulating Pk a Of Proton Acceptor supporting

confidence: 62%

ESR — A retinal protein with unusual properties from Exiguobacterium sibiricum

Petrovskaya

Balashov

Лукашев

et al. 2015

Biochemistry Moscow

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“…Values between 7.1 and 8.2 have been reported depending on experimental conditions. 17,18,20,29,30 Thus, at neutral pH, a large portion (about 50%) of PR molecules would have Asp-97 protonated. This would prevent release of the SB proton to the extracellularly oriented acceptor site.…”

Section: Photocurrents In Response To Laser Flashesmentioning

confidence: 99%

Voltage- and pH-Dependent Changes in Vectoriality of Photocurrents Mediated by Wild-type and Mutant Proteorhodopsins upon Expression in Xenopus Oocytes

Lörinczi

Verhoefen

Wachtveitl

et al. 2009

Journal of Molecular Biology

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“…15 Although GPR has a substantial homology to BR in the retinal-binding pocket and seems to share some details of the proton translocation mechanism and the photocycle, there are many structural and functional differences deserving further in-depth study. [21][22][23][24] Unlike for its haloarchaeal counterpart, the exact structure of GPR is not known as it does not produce well-diffracting three-dimensional (3D) crystals, 25 although it can form 2D crystals amenable to biophysical characterization. 26,27 The first step in structural studies of PR by SSNMR is to obtain site-specific spectroscopic assignments of its resonances.…”

Section: Introductionmentioning

confidence: 99%