1QKP

HIGH RESOLUTION X-RAY STRUCTURE OF AN EARLY INTERMEDIATE IN THE BACTERIORHODOPSIN PHOTOCYCLE

Summary for 1QKP

• Entry DOI: 10.2210/pdb1qkp/pdb
• Related: 1AP9 1AT9 1BAC 1BAD 1BCT 1BHA 1BHB 1BRD 1BRR 1BRX 1QHJ 1QKO 2BRD
• Descriptor: BACTERIORHODOPSIN, RETINAL (3 entities in total)
• Functional Keywords: photoreceptor, proton pump, membrane protein, retinal protein, intermediate state, photocycle, lipidic cubic phases
• Biological source: HALOBACTERIUM SALINARIUM
• Total number of polymer chains: 1
• Total formula weight: 27098.85

Authors

Edman, K.,Nollert, P.,Royant, A.,Belrhali, H.,Pebay-Peyroula, E.,Hajdu, J.,Neutze, R.,Landau, E.M. (deposition date: 1999-07-30, release date: 1999-10-24, Last modification date: 2024-10-09)

Primary citation

Edman, K.,Nollert, P.,Royant, A.,Belrhali, H.,Pebay-Peyroula, E.,Hajdu, J.,Neutze, R.,Landau, E.M.
High-resolution X-ray structure of an early intermediate in the bacteriorhodopsin photocycle.
Nature, 401:822-826, 1999

PubMed Abstract: Bacteriorhodopsin is the simplest known photon-driven proton pump and as such provides a model for the study of a basic function in bioenergetics. Its seven transmembrane helices encompass a proton translocation pathway containing the chromophore, a retinal molecule covalently bound to lysine 216 through a protonated Schiff base, and a series of proton donors and acceptors. Photoisomerization of the all-trans retinal to the 13-cis configuration initiates the vectorial translocation of a proton from the Schiff base, the primary proton donor, to the extracellular side, followed by reprotonation of the Schiff base from the cytoplasm. Here we describe the high-resolution X-ray structure of an early intermediate in the photocycle of bacteriorhodopsin, which is formed directly after photoexcitation. A key water molecule is dislocated, allowing the primary proton acceptor, Asp 85, to move. Movement of the main-chain Lys 216 locally disrupts the hydrogen-bonding network of helix G, facilitating structural changes later in the photocycle.

PubMed: 10548112
DOI: 10.1038/44623

Experimental method

X-RAY DIFFRACTION (2.1 Å)