Distinguished Scientist Seminar Series featuring Karen Fleming, PhD – “Chaperones play hot potato with unfolded proteins in the periplasm”

IN PERSON

Distinguished Scientist Seminar Series

Karen Fleming, PhD
Professor of Biophysics
Johns Hopkins University

Location: New Research Building Auditorium and via Zoom: https://georgetown.zoom.us/j/94358558548

Title & Abstract: 

“Chaperones play hot potato with unfolded proteins in the periplasm”

The periplasm is a ~170-200 Å wide cellular compartment surrounding a Gram–negative bacteria and bordered by two membranes, termed the “inner” (or cytoplasmic) and “outer” membrane. Both soluble and outer membrane proteins are secreted into the periplasm using the chemical potential of the energized inner membrane or cytoplasmic sources of ATP. However, the periplasm itself is devoid of an external energy source and is permeable to many small molecules, Moreover, bacterial outer membranes are not energized like their cytoplasmic counterparts. These cellular challenges and conditions raise many questions related to the mechanisms of how nascent unfolded protein chains are sorted to outer membranes and how periplasmic chaperones function to ensure efficient biogenesis of their outer membrane proteins clients. We are using a combination of experiments and computation to interrogate mechanistic models for this periplasmic process and find that a simultaneous consideration of all competing reactions leads to insight into the controls at work in this cellular compartment.