HwMR is a novel magnesium-associated protein

Ko, Ling-Ning; Lim, Guo Zhen; Chen, Xiaoru; Cai, Chun-Jie; Liu, Kuang-Ting; Yang, Chii-Shen

doi:10.1016/j.bpj.2022.06.010

Cited by 1 publication

(3 citation statements)

References 39 publications

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“…Our recent study 5 discovered HwMR as the rst mRho with Mg 2+ association, along with changes in the micro-environments surrounding both the retinal binding pocket and the D84 residue due to the presence of Mg 2+ . These alterations signi cantly impacted the overall conformation stability.…”

Section: Discussionmentioning

confidence: 89%

“…2B) as HwMR has been substantiated as an Mg 2+ -associated mRho previously. The initial ndings 5 indicated signi cant differences in the response of HwMR under varying ion concentrations.…”

Section: Protein Puri Cation and Crystal Growing Conditions For Hwmr ...mentioning

confidence: 96%

“…A previous study 9 proposed that varying retinal compositions were presented in HwMR in the dark, such as all-trans, 11-cis, and 13-cis forms; hence, we inferred that the simultaneous presence of these multiple retinal compositions might have instigated the incomplete electron density observed for the ligand. Based on the preliminary results 5 , our investigation focused on the optical properties of HwMR under the in uences of three crucial residues, conserved in BR or SRII (Fig. 3A, B) and C-terminal residues under varying cation concentrations.…”

Section: Protein Puri Cation and Crystal Growing Conditions For Hwmr ...mentioning

confidence: 99%

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A Crystallographic Study Unveils a Novel Magnesium Transporting Rhodopsin

Yang,

Ko,

Lim

et al. 2024

Preprint

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The functionally unknown Middle rhodopsin (HwMR) is microbial rhodopsin (mRho) identified in Haloquadratum walsbyi, a microbe that thrives in 2 M MgCl2 environment harmed to most microorganisms. HwMR shares conserved and functionally critical residues with both bacteriorhodopsin (BR), a proton pump, and sensory rhodopsin (SR) that function in phototaxis, even though HwMR exerts neither function. We previously reported that it uniquely associates with Mg2+. Here, we showed that HwMR was an inward magnesium regulator, evidenced by solving the atomic structures of wild-type and D84N mutant and a cell-based light-driven conductivity assay. HwMR can sense environmental Mg2+ concentration via the D84 residue according to maximum absorbance (Abs-max) and photocycle kinetics results. Furthermore, two main Mg2+ binding sites were identified in HwMR wild-type structure but not in D84N mutant. Structural analysis demonstrated that D84N induced changes in the BC-loop on the extracellular side, causing a lower hydrophobicity and disturbing resistance against external solvents. D84N also altered the local environment in solvent-excluded areas and Coulombic electrostatic potentials around the Mg2+ binding sites. On the cytoplasmic side, T216 was found to stabilize Mg2+ directly, a phenomenon also supported by optical properties experiments. Finally, a sequential model was proposed to illustrate Mg2+ transportation in HwMR.

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Section: Discussionmentioning

confidence: 89%

“…2B) as HwMR has been substantiated as an Mg 2+ -associated mRho previously. The initial ndings 5 indicated signi cant differences in the response of HwMR under varying ion concentrations.…”

Section: Protein Puri Cation and Crystal Growing Conditions For Hwmr ...mentioning

confidence: 96%

Section: Protein Puri Cation and Crystal Growing Conditions For Hwmr ...mentioning

confidence: 99%

See 1 more Smart Citation

A Crystallographic Study Unveils a Novel Magnesium Transporting Rhodopsin

Yang,

Ko,

Lim

et al. 2024

Preprint

Self Cite

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show abstract

HwMR is a novel magnesium-associated protein

Cited by 1 publication

References 39 publications

A Crystallographic Study Unveils a Novel Magnesium Transporting Rhodopsin

A Crystallographic Study Unveils a Novel Magnesium Transporting Rhodopsin

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