Work

Membrane Permeation of a Peptide: It Is Better to be Positive

Year: 2015

Type: article

Abstract: A joint experimental and computational study investigates the translocation of a tryptophan molecule through a phospholipid membrane. Time dependent spectroscopy of the tryptophan side chain determines the rate of permeation into 150 nm phospholipid vesicles. Atomically detailed simulations are conducted to calculate the free energy profiles and the permeation coefficient. Different charging conditions of the peptide (positive, negative, or zwitterion) are considered. Both experiment and simulation reproduce the qualitative trend and suggest that the fastest permeation is when the tryptophan is positively charged. The permeation mechanism, which is revealed by molecular dynamics simulations, is of a translocation assisted by a local defect. The influence of long-range electrostatic interactions, such as the membrane dipole potential on the permeation process, is not significant.

Source: The Journal of Physical Chemistry B

DOI: 10.1021/acs.jpcb.5b02122

Authors: Alfredo E. Cardenas, Rebika Shrestha, Lauren J. Webb, Ron Elber

Institution: The University of Texas at Austin

Language: English

Topic: Lipid Membrane Structure and Behavior

Subfield: Molecular Biology

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

Open Access status: green

Funders: Welch Foundation, National Institutes of Health, National Institute of General Medical Sciences

Awards: G2068707083, Long Time Dynamics of Biomolecules, G2352449292, G3601134383