TY  - GEN
A1  - Knox-Brown, Patrick
A1  - Rindfleisch, Tobias
A1  - Günther, Anne
A1  - Balow, Kim
A1  - Bremer, Anne
A1  - Walther, Dirk
A1  - Miettinen, Markus S.
A1  - Hincha, Dirk K.
A1  - Thalhammer, Anja
T1  - Similar Yet Different
BT  - Structural and Functional Diversity among Arabidopsis thaliana LEA_4 Proteins
T2  - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - The importance of intrinsically disordered late embryogenesis abundant (LEA) proteins in the tolerance to abiotic stresses involving cellular dehydration is undisputed. While structural transitions of LEA proteins in response to changes in water availability are commonly observed and several molecular functions have been suggested, a systematic, comprehensive and comparative study of possible underlying sequence-structure-function relationships is still lacking. We performed molecular dynamics (MD) simulations as well as spectroscopic and light scattering experiments to characterize six members of two distinct, lowly homologous clades of LEA_4 family proteins from Arabidopsis thaliana. We compared structural and functional characteristics to elucidate to what degree structure and function are encoded in LEA protein sequences and complemented these findings with physicochemical properties identified in a systematic bioinformatics study of the entire Arabidopsis thaliana LEA_4 family. Our results demonstrate that although the six experimentally characterized LEA_4 proteins have similar structural and functional characteristics, differences concerning their folding propensity and membrane stabilization capacity during a freeze/thaw cycle are obvious. These differences cannot be easily attributed to sequence conservation, simple physicochemical characteristics or the abundance of sequence motifs. Moreover, the folding propensity does not appear to be correlated with membrane stabilization capacity. Therefore, the refinement of LEA_4 structural and functional properties is likely encoded in specific patterns of their physicochemical characteristics.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 901 
KW  - IDP
KW  - LEA protein
KW  - abiotic stress
KW  - dehydration
KW  - conformational rearrangement
KW  - membrane stabilization
KW  - sequence-structure-function relationship
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-469419
SN  - 1866-8372
IS  - 901
ER  - 
TY  - GEN
A1  - Sowemimo, Oluwakemi T.
A1  - Knox-Brown, Patrick
A1  - Borcherds, Wade
A1  - Rindfleisch, Tobias
A1  - Thalhammer, Anja
A1  - Daughdrill, Gary W.
T1  - Conserved glycines control disorder and function in the cold-regulated protein, COR15A
T2  - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - Cold-regulated (COR) 15A is an intrinsically disordered protein (IDP) from Arabidopsis thaliana important for freezing tolerance. During freezing-induced cellular dehydration, COR15A transitions from a disordered to mostly alpha-helical structure. We tested whether mutations that increase the helicity of COR15A also increase its protective function. Conserved glycine residues were identified and mutated to alanine. Nuclear magnetic resonance (NMR) spectroscopy was used to identify residue-specific changes in helicity for wildtype (WT) COR15A and the mutants. Circular dichroism (CD) spectroscopy was used to monitor the coil-helix transition in response to increasing concentrations of trifluoroethanol (TFE) and ethylene glycol. The impact of the COR15A mutants on the stability of model membranes during a freeze-thaw cycle was investigated by fluorescence spectroscopy. The results of these experiments showed the mutants had a higher content of alpha-helical structure and the increased alpha-helicity improved membrane stabilization during freezing. Comparison of the TFE- and ethylene glycol-induced coil-helix transitions support our conclusion that increasing the transient helicity of COR15A in aqueous solution increases its ability to stabilize membranes during freezing. Altogether, our results suggest the conserved glycine residues are important for maintaining the disordered structure of COR15A but are also compatible with the formation of alpha-helical structure during freezing induced dehydration.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1089 
KW  - COR15A
KW  - late embryogenesis abundant
KW  - intrinsically disordered proteins
KW  - trifluoroethanol
KW  - nuclear magnetic resonance
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-472217
SN  - 1866-8372
IS  - 1089
ER  -