Rhodopsin from Haloquadratum walsbyi is a light-driven magnesium transporter

Ling-Ning Ko, Guo Zhen Lim, Jui-Chien Chen, Ta Ko, Guan-Yi Li and Chii-Shen Yang ()
Additional contact information
Ling-Ning Ko: National Taiwan University
Guo Zhen Lim: National Taiwan University
Jui-Chien Chen: National Taiwan University
Ta Ko: National Taiwan University
Guan-Yi Li: National Taiwan University
Chii-Shen Yang: National Taiwan University

Nature Communications, 2025, vol. 16, issue 1, 1-10

Abstract: Abstract The functionally unknown Middle rhodopsin (HwMR) is a microbial rhodopsin (mRho) identified in Haloquadratum walsbyi, an archaeon that thrives in a 2 M MgCl2 environment harmful to most other microorganisms. HwMR shares conserved and functionally critical residues with both bacteriorhodopsin (BR), a proton pump, and sensory rhodopsin II (SRII), which mediates phototaxis, even though HwMR exerts neither function. We previously reported HwMR as a unique mRho found to associate with Mg2+. Here, we show that HwMR can sense environmental Mg2+ concentration via the D84 residue according to characteristic maximum absorption wavelength shift, photocycle kinetics, and Mg2+ titration assay. X-ray crystallography of the wild-type HwMR and its D84N mutant produced two HwMR atomic structure models. Omit maps analysis of the wild-type HwMR model revealed D84 as a Mg2+ binding site. On the cytoplasmic side, omit maps also revealed Mg2+ association with T216. Both Mg2+ sites were absent in the D84N mutant. A cell-based light-driven conductivity assay provided evidence to propose that HwMR is an inward magnesium transporter, with D84 as the primary binding site and T216 as the transportation stabilizing site. A sequential model was proposed to illustrate Mg2+ transportation in HwMR.

Date: 2025
References: View references in EconPapers View complete reference list from CitEc
Citations:

Downloads: (external link)
https://www.nature.com/articles/s41467-025-59795-y Abstract (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:nat:natcom:v:16:y:2025:i:1:d:10.1038_s41467-025-59795-y

Ordering information: This journal article can be ordered from
https://www.nature.com/ncomms/

DOI: 10.1038/s41467-025-59795-y

Access Statistics for this article

Nature Communications is currently edited by Nathalie Le Bot, Enda Bergin and Fiona Gillespie

More articles in Nature Communications from Nature
Bibliographic data for series maintained by Sonal Shukla () and Springer Nature Abstracting and Indexing ().