1s4s

From Proteopedia

Reaction Intermediate in the Photocycle of PYP, intermediate occupied between 100 micro-seconds to 5 milli-seconds

Overview

We determine the number of authentic reaction intermediates in the later, stages of the photocycle of photoactive yellow protein at room, temperature, their atomic structures, and a consistent set of chemical, kinetic mechanisms, by analysis of a set of time-dependent difference, electron density maps spanning the time range from 5 micros to 100 ms. The, successful fit of exponentials to right singular vectors derived from a, singular value decomposition of the difference maps demonstrates that a, chemical kinetic mechanism holds and that structurally distinct, intermediates exist. We identify two time-independent difference maps, from which we refine the structures of the corresponding intermediates. We, thus demonstrate how structures associated with intermediate states can be, extracted from the experimental, time-dependent crystallographic data., Stoichiometric and structural constraints allow the exclusion of one, kinetic mechanism proposed for the photocycle but retain other plausible, candidate kinetic mechanisms.

About this Structure

1S4S is a Single protein structure of sequence from Halorhodospira halophila with HC4 as ligand. Full crystallographic information is available from OCA.

Reference

Protein kinetics: structures of intermediates and reaction mechanism from time-resolved x-ray data., Schmidt M, Pahl R, Srajer V, Anderson S, Ren Z, Ihee H, Rajagopal S, Moffat K, Proc Natl Acad Sci U S A. 2004 Apr 6;101(14):4799-804. Epub 2004 Mar 23. PMID:15041745

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