Events & Seminars > Event Details


4:00 pm
Room 304, Chemistry Building

Unexpected Strength of Protein Quinary Interactions


Professor Gary Pielak
University of North Carolina at Chapel Hill

Hosted by: Professor Cam Mura

Protein quinary interactions organize the cellular interior and its metabolism. Although the interactions stabilizing secondary, tertiary and quaternary protein structure are well defined, details about the protein-matrix contacts that comprise quinary structure remain elusive. This gap exists because proteins function in the crowded cellular environment, but are traditionally studied in simple buffered solutions. We employ NMR-detected H/D exchange to quantify quinary interactions between the B1 domain of protein G and the cytosol of Escherichia coli. We demonstrate that a surface mutation in this protein is 10-fold more destabilizing in cells than in buffer, a surprising result that firmly establishes the significance of quinary interactions. Remarkably, the energy involved in these interactions can be as large as the energies that stabilize specific protein complexes. These results will drive the critical task of implementing quinary structure into models for understanding the proteome.