Department Bionanoscience
Principal investigator Greg Bokinsky
E-mail address g.e.bokinsky@tudelft.nl
Website https://sites.google.com/site/bokinskylab/home
How does E. coli coordinate membrane synthesis with growth?
Supervisor: Greg Bokinsky, g.e.bokinsky@tudelft.nl
A membrane protein of unknown function has recently been found to control fatty acid synthesis. We have the tools to discover how this happens. The interested student will compare the membrane synthesis pathway of strains lacking this unusual protein to determine which step in the fatty acid or phospholipid pathways is regulated by this protein. If time allows, the student will also construct a fluorescently-tagged version of the protein to follow its localization in different growth and membrane stress conditions.
Techniques
- mass spectrometry
- live-cell fluorescence imaging
- synthetic biology
Further reading
Posttranslational control of PlsB is sufficient to coordinate membrane synthesis with growth in Escherichia coli mBio 11:e02703-19 (2020).
How does cell shape affect membrane synthesis?
Supervisor: Greg Bokinsky, g.e.bokinsky@tudelft.nl
Different lipids exhibit different preferences for membrane shapes. For instance, cardiolipin is often found in highly-curved membranes, such as the poles of bacteria and the inner cristae of mitochondria. We have preliminary evidence that the enzyme that generates cardiolipin may be directly activated by increased membrane curvature, and that the reverse reaction (breaking cardiolipin back into two phospholipids) is also driven by decreased membrane curvature. The interested student will quantify cardiolipin and other phospholipids in E. coli cells waking up from dormancy and in cells engineered to generate small and highly-curved minicells.
Techniques
- mass spectrometry
- live-cell fluorescence imaging
- synthetic biology
Further reading
A temperature-sensitive metabolic valve and a transcriptional feedback loop drive rapid homeoviscous adaptation in Escherichia coli
How does E. coli balance production of its hard and soft membranes?
Supervisor: Greg Bokinsky, g.e.bokinsky@tudelft.nl
The outer membrane of Gram-negative bacteria is asymmetric: the inner leaflet is the “usual” phospholipid leaflet, while the outer leaflet is essential steel-plate armour (lipopolysaccharides). Lipopolysaccharides are why Gram-negative bacteria are hard to kill. However, bacteria must precisely balance phospholipid production (which form “soft” membranes) with lipopolysaccharide production (“hard” membranes)… or die. (No joke.) The balancing mechanism is highly controversial, but it is thought to depend upon protein-protein interactions that detect the amount of lipopolysaccharides accumulated along the inner membrane waiting to be transported to the outer membrane. The student will construct a fluorescent biosensor that will report the protein-protein interactions in real time and determine whether this interaction is sufficient to balance phospholipid production with lipopolysaccharide production.
Techniques
- synthetic biology
- live-cell fluorescence microscopy
- mass spectrometry
Further reading
A temperature-sensitive metabolic valve and a transcriptional feedback loop drive rapid homeoviscous adaptation in Escherichia coli. Nature Communications volume 15, Article number: 9386 (2024)