Tue, 23/01/2024 - 14:00
,
Campus SB, Building E2 6, Room E04

Prof. Dr. Heiko Heerklotz
(
Host: Prof. Dr. Jochen Hub
)
Department of Pharmaceutical Technology and Biopharmacy, Universität Freiburg

Special tricks of nature’s own detergent – effects and applications of lysolipid-membrane interactions

Lysolipids such as monoacyl-glycero-phosphatidylcholines are products of phospholipases and play roles in signaling and as an energy source in biology. They and their analogs (such as miltefosine) are used as drugs, for drug delivery systems and as biological detergents for membrane protein solubilization. On their own, they for micelles and behave in a detergent-like manner but a closer look shows a number of unusual effects regarding their interaction with membranes. Lysolipids added to fluid phosphatidylcholine bilayers insert into the cis lipid leaflet but do not flip to the trans side over many hours or days. As a consequence, they induce area asymmetry the first induces the budding of very small, highly lysolipid-enriched exovesicles. This relaxed area asymmetry but is limited in extent since it “uses up” excess area of the membrane and, hence, comes to a halt as “mother vesicles” approach a smooth spherical shape. Additional lysolipid added the system is staying out of the membrane since asymmetry stress costs more energy than insertion would yield. Lysolipid-containing liposomes of dipalmitoylphosphatidylcholine (DPPC) and PEGylated lipid act as thermoresponsive drug delivery systems. The are stable and retain their cargo (e.g., doxorubicin) safely upon storage and at 37°C, when the lipid is in the gel phase. As the liposomes enter hyperthermic regions in the body, they induce a fast yet transient drug release. This had been explained by a detergent-like effect but paradoxically, other detergents induce leakage and membrane destruction upon freezing – not melting. The paradox is resolved by the finding that beyond about 5 mol% in a gel phase, lysolipids demix from the bilayer to form stable, chain-interdigitated domains with a high lysolipid content of >30 mol%. The trigger point (10 mol% lysolipid, 41°C) is a eutectic point where both phases melt at once, creating transient spots with high, membrane-permeabilizing lysolipid content.

15:00: Coffee Break

 15:15: Chetan Poojari (B7, AG Hub): Fusion peptides modulate free-energies of stalk  formation

 15:30: Cynthia Alsayyah (C10, AG Ernst): Modulating membrane compressibility using cyclodextrins to study membrane proteins

Online Link: click here

Upcoming Events

  • SFB 1027 Seminar

    Tue, 23/04/2024 - 14:00
    ,
    Campus SB, Building E2 6, Room E04

    Prof. Dr. Carsten Beta

    Biohybrid micro-transport — how motile cells move passive micro-cargo

  • SFB 1027 Seminar

    Tue, 30/04/2024 - 14:00
    ,
    Campus SB, Building E2 6, Room E04

    Prof. Dr. Abdou Rachid Thiam

    Crafting the lipid droplet proteome

  • SFB 1027 Seminar

    Tue, 14/05/2024 - 14:00
    ,
    Campus SB, E2 6, E04

    Dr. Michael Lienemann

    Enzymatic and microbial electrosynthesis for the conversion of carbon dioxide into food supplements and commodity chemicals

  • SFB 1027 Seminar

    Tue, 28/05/2024 - 14:00
    ,
    Campus SB, Building E2 6, Room E04

    Prof. Dr. Sabine Klapp

    t.b.a.

  • IRTG Intro Lecture

    Wed, 29/05/2024 - 14:00
    ,
    Campus SB, Building E2 9, Room 0.07

    Prof. Dr. Karin Jabobs

    t.b.a.

  • SFB 1027 Seminar

    Tue, 04/06/2024 - 14:00
    ,
    Campus SB, E2 6, E04

    Prof. Dr. Stefan Klumpp

    t.b.a.

  • IRTG Intro Lecture

    Tue, 11/06/2024 - 14:00
    ,
    Campus SB, Building E2 6, Room E.04

    Prof. Dr. Jochen Hub

    Everything You Always Wanted to Know About Molecular Dynamics Simulations* 

    (*But Were Afraid to Ask)

  • SFB 1027 summer camp

    Wed, 26/06/2024 - 09:00 to Fri, 28/06/2024 - 16:00
    ,
    BURG EBERNBURG 55583 Bad Kreuznach Bad Münster am Stein Ebernburg

  • SFB 1027 Seminar

    Tue, 16/07/2024 - 14:00
    ,
    Campus SB, Building E2 6, Room E04

    Prof. Dr. Jona Kayser

    t.b.a.

  • SFB 1027 Seminar

    Tue, 23/07/2024 - 14:00
    ,
    Campus SB, E2 6, E04

    Prof. Dr. Doris Heinrich

    t.b.a.

 

 

 

 

 

 

 

 

 

 

 

 

  Legal notice Privacy policy