Structure of the Ultra-High-Affinity Colicin E2 DNase-Im2 Complex

TY - JOUR

T1 - Structure of the Ultra-High-Affinity Colicin E2 DNase-Im2 Complex

AU - Wojdyla, Justyna Aleksandra

AU - Fleishman, Sarel J

AU - Baker, David

AU - Kleanthous, Colin

N1 - Copyright © 2012 Elsevier Ltd. All rights reserved.

PY - 2012/3/16

Y1 - 2012/3/16

N2 - How proteins achieve high-affinity binding to a specific protein partner while simultaneously excluding all others is a major biological problem that has important implications for protein design. We report the crystal structure of the ultra-high-affinity protein-protein complex between the endonuclease domain of colicin E2 and its cognate immunity (Im) protein, Im2 (K(d)∼10(-)(15) M), which, by comparison to previous structural and biophysical data, provides unprecedented insight into how high affinity and selectivity are achieved in this model family of protein complexes. Our study pinpoints the role of structured water molecules in conjoining hotspot residues that govern stability with residues that control selectivity. A key finding is that a single residue, which in a noncognate context massively destabilizes the complex through frustration, does not participate in specificity directly but rather acts as an organizing center for a multitude of specificity interactions across the interface, many of which are water mediated.

AB - How proteins achieve high-affinity binding to a specific protein partner while simultaneously excluding all others is a major biological problem that has important implications for protein design. We report the crystal structure of the ultra-high-affinity protein-protein complex between the endonuclease domain of colicin E2 and its cognate immunity (Im) protein, Im2 (K(d)∼10(-)(15) M), which, by comparison to previous structural and biophysical data, provides unprecedented insight into how high affinity and selectivity are achieved in this model family of protein complexes. Our study pinpoints the role of structured water molecules in conjoining hotspot residues that govern stability with residues that control selectivity. A key finding is that a single residue, which in a noncognate context massively destabilizes the complex through frustration, does not participate in specificity directly but rather acts as an organizing center for a multitude of specificity interactions across the interface, many of which are water mediated.

UR - http://www.scopus.com/inward/record.url?scp=84857636869&partnerID=8YFLogxK

U2 - 10.1016/j.jmb.2012.01.019

DO - 10.1016/j.jmb.2012.01.019

M3 - Article

C2 - 22306467

VL - 417

SP - 79

EP - 94

JO - Journal of Molecular Biology

JF - Journal of Molecular Biology

IS - 1-2

ER -