This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
1ztr
From Proteopedia
|
Solution structure of Engrailed homeodomain L16A mutant
Overview
The most controversial area in protein folding concerns its earliest, stages. Questions such as whether there are genuine folding intermediates, and whether the events at the earliest stages are just rearrangements of, the denatured state or progress from populated transition states, remain, unresolved. The problem is that there is a lack of experimental, high-resolution structural information about early folding intermediates, and denatured states under conditions that favour folding because, competent states spontaneously fold rapidly. Here we have solved directly, the solution structure of a true denatured state by nuclear magnetic, resonance under conditions that would normally favour folding, and, directly studied its equilibrium and kinetic behaviour. We engineered a, mutant of Drosophila melanogaster Engrailed homeodomain that folds and, unfolds reversibly just by changing ionic strength. At high ionic, strength, the mutant L16A is an ultra-fast folding native protein, just, like the wild-type protein; however, at physiological ionic strength it is, denatured. The denatured state is a well-ordered folding intermediate, poised to fold by docking helices and breaking some non-native, interactions. It unfolds relatively progressively with increasingly, denaturing conditions, and so superficially resembles a denatured state, with properties that vary with conditions. Such ill-defined unfolding is a, common feature of early folding intermediate states and accounts for why, there are so many controversies about intermediates versus compact, denatured states in protein folding.
About this Structure
1ZTR is a Single protein structure of sequence from Drosophila melanogaster. Full crystallographic information is available from OCA.
Reference
Solution structure of a protein denatured state and folding intermediate., Religa TL, Markson JS, Mayor U, Freund SM, Fersht AR, Nature. 2005 Oct 13;437(7061):1053-6. PMID:16222301
Page seeded by OCA on Wed Nov 21 07:39:11 2007
