BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Physics - ECPv6.3.4//NONSGML v1.0//EN CALSCALE:GREGORIAN METHOD:PUBLISH X-WR-CALNAME:Physics X-ORIGINAL-URL:https://uwm.edu/physics X-WR-CALDESC:Events for Physics REFRESH-INTERVAL;VALUE=DURATION:PT1H X-Robots-Tag:noindex X-PUBLISHED-TTL:PT1H BEGIN:VTIMEZONE TZID:America/Chicago BEGIN:DAYLIGHT TZOFFSETFROM:-0600 TZOFFSETTO:-0500 TZNAME:CDT DTSTART:20190310T080000 END:DAYLIGHT BEGIN:STANDARD TZOFFSETFROM:-0500 TZOFFSETTO:-0600 TZNAME:CST DTSTART:20191103T070000 END:STANDARD END:VTIMEZONE BEGIN:VEVENT DTSTART;TZID=America/Chicago:20190920T153000 DTEND;TZID=America/Chicago:20190920T163000 DTSTAMP:20240328T080540 CREATED:20190827T143041Z LAST-MODIFIED:20190909T142251Z UID:4480-1568993400-1568997000@uwm.edu SUMMARY:Physics Colloquium - Mark C. Williams DESCRIPTION:Mark C. Williams\, Northeastern University \nHow Proteins Use Thermodynamics to Fight Over DNA \nOptical tweezers allow us to probe the interactions of proteins with single DNA molecules and apply very small forces. Measurement of force-dependent DNA conformations allows us to quantify interactions that govern cellular function. DNA forms a stable double-helix in order to store the genetic information for most organisms. However\, in the process of replicating an organism’s genome\, the two strands of the helix must be separated to form single-stranded DNA (ssDNA). This intermediate state is vulnerable to interference from many cellular processes and is therefore tightly regulated. \nI will discuss how the protein SSB from the model bacterium E. coli uses a complex and dynamic wrapping mechanism to control access to ssDNA during normal replication. I will then describe a protein in human cells (APOBEC3G) that occupies and/or modifies ssDNA that is formed during retroviral replication\, helping to confer immunity to HIV under some conditions. APOBEC3G uses multiple biophysical and biochemical mechanisms to inhibit viral replication and induce viral mutations\, which we dissect using single molecule methods. The results demonstrate complex biophysical mechanisms that regulate ssDNA access across a range of organisms and cell types. \nEvent flyer available here URL:https://uwm.edu/physics/event/physics-colloquium-to-be-announced-2019-09-20/ LOCATION:Lapham 160\, 3209 N. Maryland Ave.\, Milwaukee\, WI\, 53211\, United States CATEGORIES:Physics Colloquia GEO:43.0757204;-87.8840564 X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=Lapham 160 3209 N. Maryland Ave. Milwaukee WI 53211 United States;X-APPLE-RADIUS=500;X-TITLE=3209 N. Maryland Ave.:geo:-87.8840564,43.0757204 END:VEVENT END:VCALENDAR