Microbial Rhodopsins

Gushchin, Ivan; Gordeliy, Valentin

doi:10.1007/978-981-10-7757-9_2

Cited by 44 publications

(31 citation statements)

References 303 publications

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“…Second, the photocycle of the protein (measured at pH 8.5) was several seconds long which is a characteristic of sensory rhodopsins 3 . Along these lines, we noted above that heliorhodopsin possesses a hydrogen bond-forming aromatic amino acid Trp246 that faces the membrane and that might change its conformation under illumination, similarly to Tyr199 in NpSRII 14,31 .…”

Section: Biological Role Of Her Subfamilymentioning

confidence: 99%

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High Resolution Structural Insights into Heliorhodopsin Family

Kovalev

Volkov

Astashkin

et al. 2019

Preprint

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Rhodopsins are the most abundant light-harvesting proteins. A new family of rhodopsins, heliorhodopsins (HeRs), was recently discovered. In opposite to the known rhodopsins their N-termini face the cytoplasm. HeRs structure and function remain unknown. We present structures of two HeR-48C12 states at 1.5 Å showing its remarkable difference from all known rhodopsins. Its internal extracellular part is completely hydrophobic, while the cytoplasmic part comprises a cavity ('active site'), surrounded by charged amino acids and containing a cluster of water molecules, presumably being a primary proton acceptor from the Schiff base. At acidic pH a planar triangle molecule (acetate) is present in the 'active site' which demonstrated its ability to maintain such anions as carbonate or nitrate. Structure-based bioinformatic analysis identified 10 subfamilies of HeRs suggesting their diverse biological functions. The structures and available data suggest an enzymatic activity of HeR-48C12 subfamily and their possible involvement into fundamental redox biological processes.

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Section: Biological Role Of Her Subfamilymentioning

confidence: 99%

“…whereas Anabaena sensory rhodopsin (ASR) utilizes a soluble transducer protein that dissociates from ASR upon illumination 3 . In case of subfamily 1, however, no conserved proteins, which could potentially be signal transducers, could be detected in the genomic neighborhood.…”

Section: Srii-like Photoreceptors Utilize Transmembrane Chemoreceptormentioning

confidence: 99%

High Resolution Structural Insights into Heliorhodopsin Family

Kovalev

Volkov

Astashkin

et al. 2019

Preprint

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“…The rhodopsins function either as light‐driven ion (H + , Cl − , Na + ) pumps, light‐gated ion channels (channelrhodopsins), or light sensors. The latter interact with soluble transducer proteins, allowing cells to orient toward or away from light [1–3]. Almost 50 years ago, archaeal bacteriorhodopsins, that is, bacteriorhodopsin and halorhodopsin from Halobacterium salinarum (formerly named Halobacterium halobium ), were the first ones to be characterized [4].…”

Section: Introductionmentioning

confidence: 99%

A simple protocol for the isolation of proteorhodopsins of the dinoflagellate Oxyrrhis marina

et al. 2020

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For the first time, native proteorhodopsins of the marine dinoflagellate Oxyrrhis marina were isolated. Total cell membrane fractions were minced in a bead beater and solubilized with the detergent Triton X‐100. Subsequent sucrose density gradient centrifugation resulted in three or four red‐colored bands. Nonsolubilized, but still red colored, membranes sedimented at the bottom. For each of these bands, absorbance maxima were registered at approximately 514–516 nm with shoulders toward shorter wavelengths (470–490 nm). Sodium dodecyl sulfate‐polyacrylamide gel electrophoresis revealed that the uppermost band represented free retinal chromophore, as it contained no protein. The other bands were almost pure proteorhodopsin fractions as the banding patterns showed one major protein of 25 kDa. Tryptic, in‐gel digestion of the 25 kDa proteins and of faint protein bands above and below 25 kDa was followed by mass spectrometry, confirming these protein bands to consist, nearly exclusively, proteorhodopsins. Only single peptides of few other proteins were detected. In total, at least seven predicted proteorhodopsin protein sequences were experimentally verified.

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“…The classic proton pumping chain of BR contains three parts: the proton uptake region, the Schiff base region and the proton release region. 5 The proton uptake region is close to the cytoplasmic side, with two key residues, T46 and D96, that mediate the proton uptake. In the Schiff base region, the proton transferring is mediated by a series of polar and hydrogen network interactions (including water molecules), with key residues T89, D85, D212 and R82.…”

mentioning

confidence: 99%