RT Journal Article
SR Electronic
T1 High Resolution Structural Insights into Heliorhodopsin Family
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 767665
DO 10.1101/767665
A1 K. Kovalev
A1 D. Volkov
A1 R. Astashkin
A1 A. Alekseev
A1 I. Gushchin
A1 J. M. Haro-Moreno
A1 A. Rogachev
A1 T. Balandin
A1 V. Borshchevskiy
A1 A. Popov
A1 G. Bourenkov
A1 E. Bamberg
A1 F. Rodriguez-Valera
A1 G. Bueldt
A1 V. Gordeliy
YR 2019
UL http://biorxiv.org/content/early/2019/09/12/767665.abstract
AB Rhodopsins are the most abundant light-harvesting proteins. A new family of rhodopsins, heliorhodopsins (HeRs), was recently discovered. In opposite to the known rhodopsins their N-termini face the cytoplasm. HeRs structure and function remain unknown. We present structures of two HeR-48C12 states at 1.5 Å showing its remarkable difference from all known rhodopsins. Its internal extracellular part is completely hydrophobic, while the cytoplasmic part comprises a cavity (’active site’), surrounded by charged amino acids and containing a cluster of water molecules, presumably being a primary proton acceptor from the Schiff base. At acidic pH a planar triangle molecule (acetate) is present in the ‘active site’ which demonstrated its ability to maintain such anions as carbonate or nitrate. Structure-based bioinformatic analysis identified 10 subfamilies of HeRs suggesting their diverse biological functions. The structures and available data suggest an enzymatic activity of HeR-48C12 subfamily and their possible involvement into fundamental redox biological processes.