Crystal structure of the proton pumping rhodopsin AR2 from marine alga Acetabularia acetabulumCrystal structure of the proton pumping rhodopsin AR2 from marine alga Acetabularia acetabulum

Structural highlights

3am6 is a 4 chain structure with sequence from Acetabularia acetabulum. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 3.2Å
Ligands:,
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

G1K3Q0_ACEAT

Publication Abstract from PubMed

Acetabularia rhodopsin (AR) is a rhodopsin from the marine plant Acetabularia acetabulum. The opsin-encoding gene from A. acetabulum, ARII, was cloned and found to be novel but homologous to that reported previously. ARII is a light-driven proton pump, as demonstrated by the existence of a photo-induced current through Xenopus oocytes expressing ARII. The photochemical reaction of ARII prepared by cell-free protein synthesis was similar to that of bacteriorhodopsin (BR), except for the lack of light-dark adaptation and the different proton release and uptake sequence. The crystal structure determined at 3.2 A resolution is the first structure of a eukaryotic member of the microbial rhodopsin family. The structure of ARII is similar to that of BR. From the cytoplasmic side to the extracellular side of the proton transfer pathway in ARII, Asp92, a Schiff base, Asp207, Asp81, Arg78, Glu199, and Ser189 are arranged in positions similar to those of the corresponding residues directly involved in proton transfer by BR. The side-chain carboxyl group of Asp92 appears to interact with the sulfhydryl group of Cys218, which is unique to ARII and corresponds to Leu223 of BR and to Asp217 of Anabaena sensory rhodopsin. The orientation of the Arg78 side chain is opposite to the corresponding Arg82 of BR. The putative absence of water molecules around Glu199 and Arg78 may disrupt the formation of the low-barrier hydrogen bond at Glu199, resulting in the "late proton release".

Crystal structure of the eukaryotic light-driven proton-pumping rhodopsin, Acetabularia rhodopsin II, from marine alga.,Wada T, Shimono K, Kikukawa T, Hato M, Shinya N, Kim SY, Kimura-Someya T, Shirouzu M, Tamogami J, Miyauchi S, Jung KH, Kamo N, Yokoyama S J Mol Biol. 2011 Sep 2;411(5):986-98. Epub 2011 Jun 25. PMID:21726566[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

See Also

References

  1. Wada T, Shimono K, Kikukawa T, Hato M, Shinya N, Kim SY, Kimura-Someya T, Shirouzu M, Tamogami J, Miyauchi S, Jung KH, Kamo N, Yokoyama S. Crystal structure of the eukaryotic light-driven proton-pumping rhodopsin, Acetabularia rhodopsin II, from marine alga. J Mol Biol. 2011 Sep 2;411(5):986-98. Epub 2011 Jun 25. PMID:21726566 doi:10.1016/j.jmb.2011.06.028

3am6, resolution 3.20Å

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