Abstract: Recording movies of single fluorescent biological molecules while in action offers unprecedented direct access to biologically important heterogeneity and dynamics; this holds true for reactions involving purified biochemical components, as well as for reactions inside the complex biological milieu of living cells. During the past few years, we have developed and used such methods (single-molecule FRET, super-resolution imaging, and single-particle tracking) to answer long-standing questions in bacterial transcription and DNA repair. Here, I will discuss examples of our in vitro work focusing on the discovery and sequence-dependence of pausing during initial transcription, and the elucidation of the intricate sequence of conformational changes that allow RNA polymerase to open promoter DNA for transcription initiation. I will also discuss examples of our in vivo single-molecule work inside living bacteria, including the exploration of the relation between chromosome organization and gene expression. Finally, I will discuss how the same methods can be used to detect bacterial pathogens and their antibiotic resistance. Our methods and biological observations are general and should apply to many other biological systems and organisms.

Biography: Achilles Kapanidis studied Chemistry at the Aristotelian Univ of Thessaloniki (Greece) and completed his PhD in Biological Chemistry at Rutgers Univ (USA). After holding research scientist positions in single-molecule biophysics at Berkeley and UCLA, he became a senior lecturer at Oxford Univ in 2005, and a Professor of Biological Physics in 2013; Prof Kapanidis has also been an ERC grant holder and is currently a Wellcome Trust Investigator.

Prof Kapanidis is currently leading a group of physical and biological scientists (the “Gene Machines” group) which studies microbial biological machinery in gene expression, maintenance, and regulation, with a focus on gene transcription and DNA repair. The main tool of the group is single-molecule fluorescence microscopy coupled with advanced image and time-series analysis; the past few years, his group has also been working on rapid and ultrasensitive detection of antibiotic resistance and pathogenic viruses, including influenza and coronaviruses. Prof Kapanidis has also been pursuing miniaturized single-molecule imaging, a project that culminated in the formation of the Oxford Nanoimaging spin-out, and for which he has won the 2019 BBSRC Innovator of the Year award.