Structure-Functional Insight into Transmembrane Helix Dimerization by Protein Engineering, Molecular Modeling and Heteronuclear NMR Spectroscopy

Abstract

The interaction between transmembrane helices is of a great interest because it directly determines biological activity of membrane proteins. Either destroying or enhancing such interactions can result in many diseases related to dysfunction of different tissues in human body. One of the most common forms of membrane proteins is a dimer containing two membrane-spanning helices associating laterally to form a tight complex. Development of new types of drugs targeting membrane proteins requires precise structural information about this class of objects. Recent development of protein engineering, optical spectroscopy, molecular modeling and heteronuclear NMR techniques made it possible studies of the nature and mechanisms of important helix-helix interactions inside the membrane mimicking supramolecular complexes. Using a robust strategy we investigated recombinant transmembrane fragments from different families of bitopic membrane proteins including receptor tyrosine kinases, amyloid precursor and pro-apoptotic proteins, which play important roles in normal and pathological conditions of human organism by providing cell signaling, maintaining cellular homeostasis and controlling cell fate. We characterized thermodynamics of transmembrane helix association, diverse helix-helix packing interfaces and obtained detailed atomistic picture of the intra- and intermolecular (protein-protein, protein-lipid and protein-water) interactions, that along with the available biochemical data provided useful insights into the membrane protein functioning in norma and pathology.This work was supported by RFBR, the Program of RAS “MCB”, the Federal Target Programs “Scientific and Pedagogical Specialists of Innovation Russia (2009-2013)” and “Research and development in priority fields of Russian scientific and technological complex in 2007-2012”.