Translocation of polysialic acid across model membranes: kinetic analysis and dynamic studies.

Abstract

Transmembrane translocation of polyion homopolymers takes place in the case of polyanionic polysialic acid (polySia), polyanionic polynucleotides and polycationic polypeptides. The purpose of this work was to determine the role of membrane electrical parameters on the kinetics of polyion translocation, the influence of polysialic acid on ion adsorption on positively charged membrane surface and the dynamics of the phospholipid hydrocarbon chains and choline group by using 1H-NMR. The analysis of polyion translocation was performed by using the electrical equivalent circuit of the membrane for the initial membrane potential equal to zero. The changes in polysialic acid flux was up to 75% after 1 ms in comparison with the zero-time flux. Both a decrease of membrane conductance and an increase of polyion chain length resulted in the diminution of this effect. An increase of praseodymium ions adsorption to positively charged liposomes and an increase of the rate of segmental movement of the -CH2 and -CH3 groups, and the choline headgrup of lipid molecules, was observed in the presence of polySia. The results show that the direction of the vectorial polyion translocation depends both on the membrane electrical properties and the degree of polymerization of the polymer, and that polysialic acid can modulate the degree of ion adsorption and the dynamics of membrane lipids.

Application of (1)H and (31)P NMR to topological description of a model of biological membrane fusion: topological description of a model of biological membrane fusion.

“…In order to observe the process of fusion first we added Ca 2+ ions and then Pr 3+ ions, thus allowing differentiation of signals assigned to the protons from choline groups of the outer and the inner layers of the membrane ( Fig. 3(1)) (Janas et al, 2001;Timoszyk & Janas, 2003). The splitting between the signals representing the two layers of the vesicle was found to decrease with time.…”

Co-expression of two distinct polysialic acids, α2,8- and α2,9-linked polymers of N-acetylneuraminic acid, in distinct glycoproteins and glycolipids in sea urchin sperm

“…In this regard, it is noted that more than 50% of the major gangliosides are enriched in the lipid rafts (Ohta et al 1999) and that the gangliosides in the sperm lipid rafts are involved in the interaction with the egg 350 kDa sperm binding protein at fertilization (Ohta et al 2000;Maehashi et al 2003). Furthermore, it should also be noted that artificial polysialoglycolipids are reported to enhance membrane fluidity of liposomes (Janas et al 2001;Timoszyk et al 2004). Since the polysialogangliosides appear to be localized in the sperm head, these glycolipids may facilitate rearrangement of the membrane proteins on the sperm surface upon sperm activation (Neill and Vacquier 2004), membrane fusion at exocytosis of acrosome reaction and sperm-egg plasma membrane fusion.…”

Myristoylated alanine‐rich C‐kinase substrate effector domain peptide improves sex‐specific recovery and axonal regrowth after spinal cord injury

“…Hydrophobic phenylalanine side chains within the MARCKS effector domain penetrate the plasma membrane lipid bilayer to form stable associations. [14][15][16][17] Polysialic acid penetrates lipid bilayers 18,19 from the outside. MARCKS and polysialic acid interact across the plasma membrane from opposite sides to stimulate polysialic acid-enhanced neuritogenesis.…”