BIOPHYSICS SEMINAR Featuring Junji Iwahara, University of Texas Medical Branch - "How do proteins scan DNA?"

Junji Iwahara

Associate Professor, Department of Biochemistry & Molecular Biology,

Sealy Center for Structural Biology & Molecular Biophysics

University of Texas Medical Branch

Abstract

When transcription factors and DNA repair/modifying enzymes perform their function, these molecules must first locate their specific target sites in the vast presence of nonspecific but structurally similar sites on DNA. We seek to better understand at both the molecular and atomic levels how the proteins scan DNA and locate the target sites. Recently we developed unique spectroscopic methods for investigating the DNA-scanning process. We use NMR spectroscopy to characterize the DNA-scanning process at an atomic level. We also use stopped-flow fluorescence spectroscopy to study the target search kinetics at a molecular level under various conditions. In this presentation, our recent results for DNA scanning by zinc-finger proteins will be shown. It will also be shown that the kinetic properties of the zinc-finger proteins can be substantially improved via engineering based on atomic-level knowledge of DNA scanning.