2qkt
From Proteopedia
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Crystal Structure of the 5th PDZ domain of InaD
Overview
The INAD scaffold organizes a multiprotein complex that is essential for proper visual signaling in Drosophila photoreceptor cells. Here we show that one of the INAD PDZ domains (PDZ5) exists in a redox-dependent equilibrium between two conformations--a reduced form that is similar to the structure of other PDZ domains, and an oxidized form in which the ligand-binding site is distorted through formation of a strong intramolecular disulfide bond. We demonstrate transient light-dependent formation of this disulfide bond in vivo and find that transgenic flies expressing a mutant INAD in which PDZ5 is locked in the reduced state display severe defects in termination of visual responses and visually mediated reflex behavior. These studies demonstrate a conformational switch mechanism for PDZ domain function and suggest that INAD behaves more like a dynamic machine rather than a passive scaffold, regulating signal transduction at the millisecond timescale through cycles of conformational change.
About this Structure
2QKT is a Single protein structure of sequence from Drosophila melanogaster. Full crystallographic information is available from OCA.
Reference
Dynamic scaffolding in a g protein-coupled signaling system., Mishra P, Socolich M, Wall MA, Graves J, Wang Z, Ranganathan R, Cell. 2007 Oct 5;131(1):80-92. PMID:17923089
Page seeded by OCA on Thu Feb 21 18:40:07 2008
