Talk abstracts
Talk on Thursday 03:15-03:30pm submitted by Vladimir Bogdanov
Functional Engineering of Calmodulin Reveals Dynamic Constraints in Redesigning Flexible Proteins
Vladimir Bogdanov (Biophysics Graduate Program, Department of Physiology and Cell Biology, The Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, Ohio, 43210), Svetlana Tikunova (Department of Physiology and Cell Biology, The Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, Ohio, 43210), Christopher N. Johnson (Department of Chemistry, Mississippi State University, Starkville, Mississippi, 39759), Robyn T. Rebbeck, Steffen Lindert (Department of Chemistry and Biochemistry, The University of California, Los Angeles, California, 90095), Sandor Gyorke (Department of Physiology and Cell Biology, The Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, Ohio, 43210)
Abstract:
Calmodulin (CaM) is a highly conserved Ca sensor that regulates hundreds of cellular targets through Ca-dependent conformational dynamics. Despite its central role in Ca signaling and disease, its evolutionary conservation and structural flexibility have suggested that CaM is resistant to rational redesign. Here, using the cardiac Ca release channel Ryanodine receptor 2 (RyR2) as a model system, we tested whether incorporating conformational dynamics into computational protein design enables functional reengineering of CaM. We first applied a static structurebased redesign to increase CaMRyR2 affinity. Although the resulting variant bound more tightly to both the RyR2 peptide and the intact channel in vitro, it distorted peptide geometry and worsened Ca leak in cardiomyocytes ex vivo. Guided by molecular dynamics simulations, we then developed a dynamic-structure redesign strategy that preserves conformational integrity while strengthening binding. The resulting CaM variant exhibited increased RyR2 affinity and reduced pathological Ca leak in a disease-relevant model. These findings show that static redesign can improve binding yet impair physiological regulation when conformational dynamics are disrupted, demonstrating that incorporating dynamic structural constraints is essential for reengineering flexible regulatory proteins and establishes a generalizable strategy for engineering dynamic proteinprotein interactions.
Keywords: Protein Engineering, Molecular Dynamics, ProteinProtein Interactions