1bb1
From Proteopedia
CRYSTAL STRUCTURE OF A DESIGNED, THERMOSTABLE HETEROTRIMERIC COILED COIL
Overview
Electrostatic interactions are often critical for determining the specificity of protein-protein complexes. To study the role of electrostatic interactions for assembly of helical bundles, we previously designed a thermostable, heterotrimeric coiled coil, ABC, in which charged residues were employed to drive preferential association of three distinct, 34-residue helices. To investigate the basis for heterotrimer specificity, we have used multiwavelength anomalous diffraction (MAD) analysis to determine the 1.8 A resolution crystal structure of ABC. The structure shows that ABC forms a heterotrimeric coiled coil with the intended arrangement of parallel chains. Over half of the ion pairs engineered to restrict helix associations were apparent in the experimental electron density map. As seen in other trimeric coiled coils, ABC displays acute knobs-into-holes packing and a buried anion coordinated by core polar amino acids. These interactions validate the design strategy and illustrate how packing and polar contacts determine structural uniqueness.
About this Structure
Full crystallographic information is available from OCA.
Reference
Crystal structure of a designed, thermostable, heterotrimeric coiled coil., Nautiyal S, Alber T, Protein Sci. 1999 Jan;8(1):84-90. PMID:10210186 Page seeded by OCA on Fri May 2 11:17:39 2008
