TY  - JOUR
A1  - Navarro-Retamal, Carlos
A1  - Bremer, Anne
A1  - Alzate-Morales, Jans H.
A1  - Caballero, Julio
A1  - Hincha, Dirk K.
A1  - Gonzalez, Wendy
A1  - Thalhammer, Anja
T1  - Molecular dynamics simulations and CD spectroscopy reveal hydration-induced unfolding of the intrinsically disordered LEA proteins COR15A and COR15B from Arabidopsis thaliana
JF  - Physical chemistry, chemical physics : a journal of European Chemical Societies
N2  - The LEA (late embryogenesis abundant) proteins COR15A and COR15B from Arabidopsis thaliana are intrinsically disordered under fully hydrated conditions, but obtain alpha-helical structure during dehydration, which is reversible upon rehydration. To understand this unusual structural transition, both proteins were investigated by circular dichroism (CD) and molecular dynamics (MD) approaches. MD simulations showed unfolding of the proteins in water, in agreement with CD data obtained with both HIS-tagged and untagged recombinant proteins. Mainly intramolecular hydrogen bonds (H-bonds) formed by the protein backbone were replaced by H-bonds with water molecules. As COR15 proteins function in vivo as protectants in leaves partially dehydrated by freezing, unfolding was further assessed under crowded conditions. Glycerol reduced (40%) or prevented (100%) unfolding during MD simulations, in agreement with CD spectroscopy results. H-bonding analysis indicated that preferential exclusion of glycerol from the protein backbone increased stability of the folded state.
Y1  - 2016
U6  - https://doi.org/10.1039/c6cp02272c
SN  - 1463-9076
SN  - 1463-9084
VL  - 18
SP  - 25806
EP  - 25816
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - GEN
A1  - Navarro-Retamal, Carlos
A1  - Bremer, Anne
A1  - Alzate-Morales, Jans H.
A1  - Caballero, Julio
A1  - Hincha, Dirk K.
A1  - González, Wendy
A1  - Thalhammer, Anja
T1  - Molecular dynamics simulations and CD spectroscopy reveal hydration-induced unfolding of the intrinsically disordered LEA proteins COR15A and COR15B from Arabidopsis thaliana
N2  - The LEA (late embryogenesis abundant) proteins COR15A and COR15B from Arabidopsis thaliana are intrinsically disordered under fully hydrated conditions, but obtain α-helical structure during dehydration, which is reversible upon rehydration. To understand this unusual structural transition, both proteins were investigated by circular dichroism (CD) and molecular dynamics (MD) approaches. MD simulations showed unfolding of the proteins in water, in agreement with CD data obtained with both HIS-tagged and untagged recombinant proteins. Mainly intramolecular hydrogen bonds (H-bonds) formed by the protein backbone were replaced by H-bonds with water molecules. As COR15 proteins function in vivo as protectants in leaves partially dehydrated by freezing, unfolding was further assessed under crowded conditions. Glycerol reduced (40%) or prevented (100%) unfolding during MD simulations, in agreement with CD spectroscopy results. H-bonding analysis indicated that preferential exclusion of glycerol from the protein backbone increased stability of the folded state.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 321 
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-394503
SP  - 25806
EP  - 25816
ER  - 
TY  - JOUR
A1  - Navarro-Retamal, Carlos
A1  - Bremer, Anne
A1  - Ingolfsson, Helgi I.
A1  - Alzate-Morales, Jans
A1  - Caballero, Julio
A1  - Thalhammer, Anja
A1  - Gonzalez, Wendy
A1  - Hincha, Dirk K.
T1  - Folding and Lipid Composition Determine Membrane Interaction of the Disordered Protein COR15A
JF  - Biophysical journal
N2  - Plants from temperate climates, such as the model plant Arabidopsis thaliana, are challenged with seasonal low temperatures that lead to increased freezing tolerance in fall in a process termed cold acclimation. Among other adaptations, this involves the accumulation of cold-regulated (COR) proteins, such as the intrinsically disordered chloroplast-localized protein COR15A. Together with its close homolog COR15B, it stabilizes chloroplast membranes during freezing. COR15A folds into amphipathic alpha-helices in the presence of high concentrations of low-molecular-mass crowders or upon dehydration. Under these conditions, the (partially) folded protein binds peripherally to membranes. In our study, we have used coarse-grained molecular dynamics simulations to elucidate the details of COR15A-membrane binding and its effects on membrane structure and dynamics. Simulation results indicate that at least partial folding of COR15A and the presence of highly unsaturated galactolipids in the membranes are necessary for efficient membrane binding. The bound protein is stabilized on the membrane by interactions of charged and polar amino acids with galactolipid headgroups and by interactions of hydrophobic amino acids with the upper part of the fatty acyl chains. Experimentally, the presence of liposomes made from a mixture of lipids mimicking chloroplast membranes induces additional folding in COR15A under conditions of partial dehydration, in agreement with the simulation results.
Y1  - 2018
U6  - https://doi.org/10.1016/j.bpj.2018.08.014
SN  - 0006-3495
SN  - 1542-0086
VL  - 115
IS  - 6
SP  - 968
EP  - 980
PB  - Cell Press
CY  - Cambridge
ER  -