1uwn

From Proteopedia

Revision as of 16:05, 18 December 2007

THE INITIAL EVENTS IN THE PHOTOCYCLE OF PHOTOACTIVE YELLOW PROTEIN: A COMMON MECHANISM ON LIGHT ACTIVATION IN PHOTORECEPTOR PROTEINS

Overview

The light-induced isomerization of a double bond is the key event that, allows the conversion of light energy into a structural change in, photoactive proteins for many light-mediated biological processes, such as, vision, photosynthesis, photomorphogenesis, and photo movement. Cofactors, such as retinals, linear tetrapyrroles, and 4-hydroxy-cinnamic acid have, been selected by nature that provide the essential double bond to, transduce the light signal into a conformational change and eventually, a, physiological response. Here we report the first events after light, excitation of the latter chromophore, containing a single ethylene double, bond, in a low temperature crystallographic study of the photoactive, yellow protein. We measured experimental phases to overcome possible model, bias, corrected for minimized radiation damage, and measured absorption, spectra of crystals to analyze the photoproducts formed. The data show a, mechanism for the light activation of photoactive yellow protein, where, the energy to drive the remainder of the conformational changes is stored, in a slightly strained but fully cis-chromophore configuration. In, addition, our data indicate a role for backbone rearrangements during the, very early structural events.

About this Structure

1UWN is a Single protein structure of sequence from Halorhodospira halophila with SO4 and HC4 as ligands. Known structural/functional Site: . Full crystallographic information is available from OCA.

Reference

Initial events in the photocycle of photoactive yellow protein., Kort R, Hellingwerf KJ, Ravelli RB, J Biol Chem. 2004 Jun 18;279(25):26417-24. Epub 2004 Mar 16. PMID:15026418

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