Light-driven anion-pumping rhodopsin with unique cytoplasmic anion-release mechanism

Microbial rhodopsins are photoreceptive membrane proteins found in microorganisms with an all-trans-retinal chromophore. The function of many microbial rhodopsins is determined by three residues in the third transmembrane helix called motif residues. Here, we report a group of microbial rhodopsins w...

Full description

Saved in:
Bibliographic Details
Published inThe Journal of biological chemistry Vol. 300; no. 10; p. 107797
Main Authors Ishizuka, Tomohiro, Suzuki, Kano, Konno, Masae, Shibata, Keisei, Kawasaki, Yuma, Akiyama, Hidefumi, Murata, Takeshi, Inoue, Keiichi
Format Journal Article
LanguageEnglish
Published United States Elsevier Inc 01.10.2024
American Society for Biochemistry and Molecular Biology
Subjects
anion pump
microbial rhodopsin
photoreceptor
rhodopsin
spectroscopy
X-ray crystallography
RSB
microbial rhodopsin
TTG
photoreceptor
pKa
NpHR
HR
DDM
rhodopsin
X-ray crystallography
BR
GHR
CCCP
spectroscopy
SsGHR
SyHR
Kd
TM
anion pump
WT
EC
Online AccessGet full text

Cover

More Information
Summary:Microbial rhodopsins are photoreceptive membrane proteins found in microorganisms with an all-trans-retinal chromophore. The function of many microbial rhodopsins is determined by three residues in the third transmembrane helix called motif residues. Here, we report a group of microbial rhodopsins with a novel Thr–Thr–Gly (TTG) motif. The ion-transport assay revealed that they function as light-driven inward anion pumps similar to halorhodopsins previously found in archaea and bacteria. Based on the characteristic glycine residue in their motif and light-driven anion-pumping function, these new rhodopsins are called glycylhalorhodopsins (GHRs). X-ray crystallographic analysis found large cavities on the cytoplasmic side, which are produced by the small side-chain volume of the glycine residue in the motif. The opened structure of GHR on the cytoplasmic side is related to the anion releasing process to the cytoplasm during the photoreaction compared to canonical halorhodopsin from Natronomonas pharaonis (NpHR). GHR also transports SO42– and the extracellular glutamate residue plays an essential role in extracellular SO42– uptake. In summary, we have identified TTG motif-containing microbial rhodopsins that display an anion-releasing mechanism.
Bibliography:ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
content type line 23
ISSN:0021-9258
1083-351X
1083-351X
DOI:10.1016/j.jbc.2024.107797