Title: “Single-molecule studies of DNA-binding proteins and caveats.”
Single-molecule techniques are powerful tools for studying the functions of biological entities by investigating individual molecules. In this talk, Dr. Kim will discuss how single-molecule DNA flow-stretching assay can help elucidate underlying working mechanisms of DNA-binding proteins using ParB protein as an example. ParB proteins play a crucial role in low-copy-number plasmid and chromosome partitioning and segregation in bacteria. They bind to specific DNA sequences called parS with a high affinity, but ParB proteins associate with a 10-20 kb region encompassing parS, a phenomenon termed spreading. Recent paradigm-shifting discoveries revealed that ParB protein is a novel enzyme that utilizes cytidine triphosphate (CTP) to modulate its functions. Dr. Kim’s team employed single-molecule techniques to elucidate the roles of CTP and found that CTP prevents the random recruitment of BsParB proteins. If time permits, Dr. Kim will discuss the team’s surprising finding that a small KCK-tag that is commonly used in fluorescent dye labeling on a protein leads to unexpected artifacts.
