7U55

Crystal structure of Thermoplasmatales archaeon heliorhodopsin at pH 4.5

7U55 の概要

• エントリーDOI: 10.2210/pdb7u55/pdb
• 分子名称: Heliorhodopsin, RETINAL, CHLORIDE ION, ... (5 entities in total)
• 機能のキーワード: microbial rhodopsin, retinal protein, heliorhodopsin, seven transmembrane protein, membrane protein
• 由来する生物種: Thermoplasmatales archaeon SG8-52-1
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 30411.98

構造登録者

Besaw, J.E.,De Guzman, P.,Miller, R.J.D.,Ernst, O.P. (登録日: 2022-03-01, 公開日: 2022-09-07, 最終更新日: 2024-11-06)

主引用文献

Besaw, J.E.,Reichenwallner, J.,De Guzman, P.,Tucs, A.,Kuo, A.,Morizumi, T.,Tsuda, K.,Sljoka, A.,Miller, R.J.D.,Ernst, O.P.
Low pH structure of heliorhodopsin reveals chloride binding site and intramolecular signaling pathway.
Sci Rep, 12:13955-13955, 2022

PubMed Abstract: Within the microbial rhodopsin family, heliorhodopsins (HeRs) form a phylogenetically distinct group of light-harvesting retinal proteins with largely unknown functions. We have determined the 1.97 Å resolution X-ray crystal structure of Thermoplasmatales archaeon SG8-52-1 heliorhodopsin (TaHeR) in the presence of NaCl under acidic conditions (pH 4.5), which complements the known 2.4 Å TaHeR structure acquired at pH 8.0. The low pH structure revealed that the hydrophilic Schiff base cavity (SBC) accommodates a chloride anion to stabilize the protonated retinal Schiff base when its primary counterion (Glu-108) is neutralized. Comparison of the two structures at different pH revealed conformational changes connecting the SBC and the extracellular loop linking helices A-B. We corroborated this intramolecular signaling transduction pathway with computational studies, which revealed allosteric network changes propagating from the perturbed SBC to the intracellular and extracellular space, suggesting TaHeR may function as a sensory rhodopsin. This intramolecular signaling mechanism may be conserved among HeRs, as similar changes were observed for HeR 48C12 between its pH 8.8 and pH 4.3 structures. We additionally performed DEER experiments, which suggests that TaHeR forms possible dimer-of-dimer associations which may be integral to its putative functionality as a light sensor in binding a transducer protein.

PubMed: 35977989
DOI: 10.1038/s41598-022-17716-9

実験手法

X-RAY DIFFRACTION (1.97 Å)