Speaker: Leo Golubovitch, University of West Virginia
Time: October 9, 2014 16:00 -17:00
Biological macromolecules are inherently capable of forming physically interesting self- assembled structures with biologically significant functionalities. We overview the efforts to theoretically understand and possibly control some of these fascinating structures and phenomena. Prominent recent examples for this are novel partially ordered liquid crystalline phases, such as the sliding phases of DNA-cationic lipid complexes used for gene therapy applications in the battles against cancer. Other examples discussed in this talk involve the conformational behavior of DNA molecules adsorbed on lipid membranes that are supported on grooved nanostructured surfaces. Aided by theoretical insights, experimental researchers have discovered that the edges formed on these supported membranes can adsorb and completely orient (stretch) very long DNA molecules. This stretching allows direct imaging (by the common fluorescence microscopy) of fundamental biological processes of the interactions between DNA and single protein molecules. In the last part of this talk, we describe our theoretical quest to elucidate the interactions of antimicrobial peptide molecules with biological membranes. Antimicrobial peptides are secreted by organisms of plants and animals, and they serve as defense weapons (natural antibiotics) in the battles against bacteria. We elucidate a rich variety of cell membrane morphological changes induced by peptides, such as pore formation, membrane corrugation and Euler buckling, and we try to answer a very basic question on how these peptide molecules kill bacteria.