Disputation: Julia Anna Weikum
Doctoral candidate Julia Anna Weikum at the Department of Pharmacy, Faculty of Mathematics and Natural Sciences, is defending the thesis "Bacterial protein systems at the membrane interface: Structural and biophysical studies of the E.coli adhesion receptor intimin and the magnesium transporter MgtA" for the degree of Philosophiae Doctor.
The PhD defence will be fully digital and streamed directly using Zoom. The host of the session will moderate the technicalities while the chair of the defence will moderate the disputation.
Ex auditorio questions: the chair of the defence will invite the audience to ask ex auditorio questions either written or oral. This can be requested by clicking 'Participants -> Raise hand'.
Transport across bacterial membranes
Main research findings
Bacterial protein systems at the membrane interface
Pathogenic Escherichia coli, such as EPEC and EHEC, remain a global threat, responsible for millions of acute diseases worldwide. The dissertation by Julia Weikum investigates two E. coli proteins, which are involved with the bacterial infection and drug resistance process.
During the infection, EPEC and EHEC attach to the intestinal tract via an adhesion protein, called intimin, which binds to the intestinal surface through its extracellular section. Julia Weikum determined the atomic structures of the last two elusive extracellular domains, sitting closest to the membrane interface. These domains form a stiff base of the protruding extracellular rod, and Julia proposed that the intimin binding probability increases with higher stiffness in the extracellular base.
Julia further worked on the bacterial magnesium transporter MgtA. MgtA has been linked to bacterial survival in conditions with low magnesium levels, such as induced by the human immune response during infection. The identification of factors regulating MgtA function is desired to develop drugs controlling its cellular role. Julia could show that two different, but highly specific lipids influence the activity of MgtA. This is the first case described in the literature of two lipids, which individually only have little influence on the enzyme activity, however when combined promote strong activation.
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