XXII. BIOCHEMICKÝ ZJAZD - Jesseniova lekárska fakulta

Lectures
LIPID HELICES formaTION IN BaCILLUS SUBTILIS CELL MEMBraNE
Imrich Barák, Katarína Muchová, Nada Pavlendová and Ján Jamroškovič
Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská cesta 21,
845 51 Bratislava, Slovakia
The domains of different lipid composition are present in eukaryotic and prokaryotic cell
membranes. Using membrane binding fluorescent dyes, we demonstrate previously, the
presence of lipid spirals extending along the long-axis of cells of the rod-shaped bacterium
B. subtilis. These data indicate a higher level of membrane lipid organization than
previously observed. Little is known however of the origin of these helical structures.
Principally, there are at least three main specifically localized molecular structures in
the membrane or close proximity to it what can help to form or influence the formation
of lipid helixes. In our work we have focused on analyzing these lipid structures in correlation
with other above mentioned helical structures in the cell membrane or its close
proximity. We were analyzing lipid domains by using lipid specific dyes in protoplasted
cells, in Mbl, MreB and MreBH mutant strains. We have used FRAP and FRET experiments
to determine dynamics of lipid domains and co-localization of lipid dyes with GFP fused
proteins, respectively.
We have also studied the role of lipid helices in cell division by directing the Min system
to the helices from pole to pole. We inspected cell division when E. coli Min-system was
introduced into B. subtilis cells. We show that MinD Ec
can partially substitute function of
its B. subtilis protein counterpart. Additionally, we observed dynamic behavior of MinD Ec
and MinE in B. subtilis when expressed together. All these findings indicate that these
two Min systems resemble each other more than was thought previously
42 XXII. Biochemistry Congress, Martin