2za4

From Proteopedia

---

Revision as of 18:48, 22 May 2008

proteopedia linkproteopedia link

Template:STRUCTURE 2za4

Crystal Structural Analysis of Barnase-barstar Complex

Overview

The complex of barnase (bn) and barstar (bs), which has been widely studied as a model for quantitative analysis of protein-protein interactions, is significantly destabilized by a single mutation, namely, bs Asp39 --> Ala, which corresponds to a change of 7.7 kcal.mol(-1) in the free energy of binding. However, there has been no structural information available to explain such a drastic destabilization. In the present study, we determined the structure of the mutant complex at 1.58 A resolution by X-ray crystallography. The complex was similar to the wild-type complex in terms of overall and interface structures; however, the hydrogen bond network mediated by water molecules at the interface was significantly different. Several water molecules filled the cavity created by the mutation and consequently caused rearrangement of the hydrated water molecules at the interface. The water molecules were redistributed into a channel-like structure that penetrated into the complex. Furthermore, molecular dynamics simulations showed that the mutation increased the mobility of water molecules at the interface. Since such a drastic change in hydration was not observed in other mutant complexes of bn and bs, the significant destabilization of the interaction may be due to this channel-like structure of hydrated water molecules.

About this Structure

2ZA4 is a Protein complex structure of sequences from Bacillus amyloliquefaciens. Full crystallographic information is available from OCA.

Reference

Crystal structural analysis of protein-protein interactions drastically destabilized by a single mutation., Urakubo Y, Ikura T, Ito N, Protein Sci. 2008 Apr 25;. PMID:18441234 Page seeded by OCA on Thu May 22 21:48:04 2008