The association of defensin HNP-2 with negatively charged membranes : A combined fluorescence and linear dichroism study

Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved..

The association of defensin HNP-2 with negatively charged membranes has been studied using a new approach that combines fluorescence and linear dichroism (LD) spectroscopies with simulated LD spectra in order to characterise the binding kinetics and bound configurations of the peptide. Binding to membranes composed of mixtures of diacylglycerophosphocholines (PC) with either diacylglycerophosphoglycerol (PG) or diacylglycerophosphoserine (PS) was conducted at lipid:peptide ratios that yielded binding, but not membrane fusion. HNP-2 association with membranes under these conditions was a 2 stage-process, with both stages exhibiting first order kinetics. The fast initial step, with a half-life of < 1 min, was followed by a slower step with a half-life of > 3 min. Conversion between the states was estimated to have an enthalpy of activation of approximately 10 kJ mol(-1) and an entropy of activation of -0.2 kJ K mol(-1). LD spectra corresponding to each of the membrane bound states were generated by non-linear regression using a standard kinetic model. These spectra are interpreted in comparison with spectra calculated using the program Dichrocalc and reveal that the peptide associates with membranes in a small number of stable configurations. All of these configurations have a significant proportion of β-sheet structure residing in the plane of the membrane. Two configurations support structures previously proposed for defensins in membranes.

Medienart:

E-Artikel

Erscheinungsjahr:

2016

Erschienen:

2016

Enthalten in:

Zur Gesamtaufnahme - volume:1858

Enthalten in:

Biochimica et biophysica acta - 1858(2016), 4 vom: 31. Apr., Seite 892-903

Sprache:

Englisch

Beteiligte Personen:

Pridmore, Catherine J [VerfasserIn]
Rodger, Alison [VerfasserIn]
Sanderson, John M [VerfasserIn]

Links:

Volltext

Themen:

Antibiotic peptide
Binding
Defensins
Fluorescence
Journal Article
Kinetics
Linear dichroism
Lipid Bilayers
Lipid membrane
Neutrophil defensin hNP2, human
Research Support, Non-U.S. Gov't

Anmerkungen:

Date Completed 17.06.2016

Date Revised 26.11.2016

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1016/j.bbamem.2016.01.014

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM25675537X