Naturally evolved G protein-coupled receptors adopt metastable conformations

作者：Chen Kuang Yui Michael; Zhou Fuguo; Fryszczyn Bartlomiej G; Barth Patrick^*

来源：Proceedings of the National Academy of Sciences of the United States of America, 2012, 109(33): 13284-13289.

DOI：10.1073/pnas.1205512109

• computational protein design
• protein conformational stability
• membrane protein modeling
• signal transduction
• synthetic biology

A wide range of membrane receptors signal through conformational changes, and the resulting protein conformational flexibility often hinders their structural studies. Because the determinants of membrane receptor conformational stability are still poorly understood, identifying a minimal set of perturbations stabilizing a membrane protein in a given conformation remains a major challenge in membrane protein structure determination. We present a novel approach integrating bioinformatics, computational design and experimental techniques that identifies and stabilizes metastable receptor regions. When applied to the beta1-adrenergic receptor, the method generated 13 novel receptor variants stabilized in the intended inactive state among which two exhibit an apparent thermostability higher than WT and M23 (a receptor variant previously stabilized by extensive scanning mutagenesis) by more than 30 degrees C and 11 degrees C, respectively. Targeted regions involve nonconserved unsatisfied polar residues or exhibit significant packing defects, features found in all class A G protein-coupled receptor structures. These findings suggest that natural G protein-coupled receptor sequences have evolved to be conformationally metastable through the design of suboptimal polar and van der Waals tertiary interactions. Given sufficiently accurate structural models, our approach should prove useful for designing stabilized variants of many un-characterized membrane receptors.

• 出版日期2012-8-14