2NH and 3OH are crucial structural requirements in sphingomyelin for sticholysin II binding and pore formation in bilayer membranes

A1 Journal article (refereed)


Internal Authors/Editors


Publication Details

List of Authors: Maula T, Isaksson YJE, Garcia-Linares S, Niinivehmas S, Pentikainen OT, Kurita M, Yamaguchi S, Yamamoto T, Katsumura S, Gavilanes JG, Martinez-del-Pozo A, Slotte JP
Publisher: ELSEVIER SCIENCE BV
Publication year: 2013
Journal: BBA - Biomembranes
Journal acronym: BBA-BIOMEMBRANES
Volume number: 1828
Issue number: 5
Start page: 1390
End page: 1395
Number of pages: 6
ISSN: 0005-2736
eISSN: 1879-2642


Abstract

Sticholysin II (StnII) is a pore-forming toxin from the sea anemone Stichodactyla heliantus which belongs to the large actinoporin family. The toxin binds to sphingomyelin (SM) containing membranes, and shows high binding specificity for this lipid. In this study, we have examined the role of the hydrogen bonding groups of the SM long-chain base (i.e., the 2NH and the 3OH) for StnII recognition. We prepared methylated SM-analogs which had reduced hydrogen bonding capability from 2NH and 3OH. Both surface plasmon resonance experiments, and isothermal titration calorimetry measurements indicated that Stall failed to bind to bilayers containing methylated SM-analogs, whereas clear binding was seen to SM-containing bilayers. Stall also failed to induce calcein release (i.e., pore formation) from vesicles made to contain methylated SM-analogs, but readily induced calcein release from SM-containing vesicles. Molecular modeling of SM docked to the phosphocholine binding site of StnII indicated that the 2NH and 3OH groups were likely to form a hydrogen bond with Tyr135. In addition, it appeared that Tyr111 and Tyr136 could donate hydrogen bonds to phosphate oxygen, thus stabilizing SM binding to the toxin. We conclude that the interfacial hydrogen bonding properties of SM, in addition to the phosphocholine head group, are crucial for high-affinity SM/StnII-interaction. (C) 2013 Elsevier B.V. All rights reserved.


Keywords

Isothermal titration calorimetry, Membrane permeabilization, Molecular docking, Surface plasmon resonance

Last updated on 2019-22-07 at 04:52