Reconciliation of opposing views on membrane–sugar interactions

TY - JOUR

T1 - Reconciliation of opposing views on membrane–sugar interactions

AU - Andersen, Heidi D.

AU - Wang, Chunhua

AU - Arleth, Lise

AU - Peters, Günther H.J.

AU - Westh, Peter

PY - 2011/2/1

Y1 - 2011/2/1

N2 - It is well established that small sugars exert different types of stabilization of biomembranes both in vivo and in vitro. However, the essential question of whether sugars are bound to or expelled from membrane surfaces, i.e., the sign and size of the free energy of the interaction, remains unresolved, and this prevents a molecular understanding of the stabilizing mechanism. We have used small-angle neutron scattering and thermodynamic measurements to show that sugars may be either bound or expelled depending on the concentration of sugar. At low concentration, small sugars bind quite strongly to a lipid bilayer, and the accumulation of sugar at the interface makes the membrane thinner and laterally expanded. Above ∼0.2 M the sugars gradually become expelled from the membrane surface, and this repulsive mode of interaction counteracts membrane thinning. The dual nature of sugar-membrane interactions offers a reconciliation of conflicting views in earlier reports on sugar-induced modulations of membrane properties.

AB - It is well established that small sugars exert different types of stabilization of biomembranes both in vivo and in vitro. However, the essential question of whether sugars are bound to or expelled from membrane surfaces, i.e., the sign and size of the free energy of the interaction, remains unresolved, and this prevents a molecular understanding of the stabilizing mechanism. We have used small-angle neutron scattering and thermodynamic measurements to show that sugars may be either bound or expelled depending on the concentration of sugar. At low concentration, small sugars bind quite strongly to a lipid bilayer, and the accumulation of sugar at the interface makes the membrane thinner and laterally expanded. Above ∼0.2 M the sugars gradually become expelled from the membrane surface, and this repulsive mode of interaction counteracts membrane thinning. The dual nature of sugar-membrane interactions offers a reconciliation of conflicting views in earlier reports on sugar-induced modulations of membrane properties.

U2 - 10.1073/pnas.1012516108

DO - 10.1073/pnas.1012516108

M3 - Journal article

C2 - 21245346

SN - 0027-8424

VL - 108

SP - 1874

EP - 1878

JO - Proceedings of the National Academy of Sciences of the United States of America

JF - Proceedings of the National Academy of Sciences of the United States of America

IS - 5

ER -