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ID 57389
Author
Shibukawa, Atsushi Graduate School of Medicine, Dentistry and Pharmaceutical Sciences , Okayama University
Kojima, Keiichi Graduate School of Medicine, Dentistry and Pharmaceutical Sciences , Okayama University
Nakajima, Yu Atmosphere and Ocean Research Institute , The University of Tokyo
Nishimura, Yosuke Atmosphere and Ocean Research Institute , The University of Tokyo
Yoshizawa, Susumu Atmosphere and Ocean Research Institute , The University of Tokyo
Sudo, Yuki Graduate School of Medicine, Dentistry and Pharmaceutical Sciences , Okayama University ORCID Kakenhi
Abstract
Many microorganisms express rhodopsins, pigmented membrane proteins capable of absorbing sunlight and harnessing that energy for important biological functions such as ATP synthesis and phototaxis. Microbial rhodopsins that have been discovered to date are categorized as type-1 rhodopsins. Interestingly, researchers have very recently unveiled a new microbial rhodopsin family named the heliorhodopsins, which are phylogenetically distant from type-1 rhodopsins. Among them, only heliorhodopsin-48C12 (HeR-48C12) from a Gram-positive eubacterium has been photochemically characterized [Pushkarev, A., et al. (2018) Nature 558, 595-599]. In this study, we photochemically characterize a purple-colored heliorhodopsin from Gram-negative eubacterium Bellilinea caldifistulae (BcHeR) as a second example and identify which properties are or are not conserved between BcHeR and HeR-48C12. A series of photochemical measurements revealed several conserved properties between them, including a visible absorption spectrum with a maximum at around 550 nm, the lack of ion-transport activity, and the existence of a second-order O-like intermediate during the photocycle that may activate an unidentified biological function. In contrast, as a property that is not conserved, although HeR-48C12 shows the light adaptation state of retinal, BcHeR showed the same retinal configuration under both dark- and light-adapted conditions. These comparisons of photochemical properties between BcHeR and HeR-48C12 are an important first step toward understanding the nature and functional role of heliorhodopsins.
Note
This fulltext will be available in Jun 2020
Published Date
2019-05-31
Publication Title
Biochemistry
Volume
volume58
Issue
issue26
Publisher
American Chemical Society
Start Page
2934
End Page
2943
ISSN
00062960
NCID
AA00564599
Content Type
Journal Article
language
英語
OAI-PMH Set
岡山大学
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author
PubMed ID
DOI
Related Url
isVersionOf https://doi.org/10.1021/acs.biochem.9b00257