TY - JOUR
T1 - Zinc induces disorder-to-order transitions in free and membrane-associated Thellungiella salsuginea dehydrins TsDHN-1 and TsDHN-2
T2 - a solution CD and solid-state ATR-FTIR study.
AU - Rahman, Luna N.
AU - Bamm, Vladimir V.
AU - Voyer, Janine A.M.
AU - Smith, Graham S.T.
AU - Chen, Lin
AU - Yaish, Mahmoud W.
AU - Moffatt, Barbara A.
AU - Dutcher, John R.
AU - Harauz, George
N1 - Funding Information:
This work was supported by the Natural Sciences and Engineering Research Council of Canada (G.H.) and initially by the Advanced Food and Materials Network (AFMNet, B.A.M., J.R.D., G.H.), a national Network of Centres of Excellence. J.R.D. acknowledges support from the Canada Research Chair Program. The authors are grateful to Dr. David Libich for assistance with Fig. , to Mr. Miguel De Avila for help with the isothermal titration calorimetry and to Dr. Leonid Brown of the University of Guelph for many helpful discussions on FTIR data collection and analysis.
PY - 2011/5
Y1 - 2011/5
N2 - Dehydrins are intrinsically unstructured proteins that are expressed in plants experiencing extreme environmental conditions such as drought or low temperature. Although their role is not completely understood, it has been suggested that they stabilize proteins and membrane structures during environmental stress and also sequester metals such as zinc. Here, we investigate two dehydrins (denoted as TsDHN-1 and TsDHN-2) from Thellungiella salsuginea. This plant is a crucifer that thrives in the Canadian sub-Arctic (Yukon Territory) where it grows on saline-rich soils and experiences periods of both extreme cold and drought. We show using circular dichroism and attenuated total reflection-Fourier transform infrared spectroscopy that ordered secondary structure is induced and stabilized in these proteins, both in free and vesicle-bound form, by association with zinc. In membrane-associated form, both proteins have an increased proportion of β-strand conformation induced by the cation, in addition to the amphipathic α-helices formed by their constituent K-segments. These results support the hypothesis that dehydrins stabilize plant plasma and organellar membranes in conditions of stress, and further that zinc may be an important co-factor in stabilization. Whereas dehydrins in the cytosol of a plant cell undergoing dehydration or temperature stress form bulk hydrogels and remain primarily disordered, dehydrins with specific membrane- or protein-associations will have induced ordered secondary structures.
AB - Dehydrins are intrinsically unstructured proteins that are expressed in plants experiencing extreme environmental conditions such as drought or low temperature. Although their role is not completely understood, it has been suggested that they stabilize proteins and membrane structures during environmental stress and also sequester metals such as zinc. Here, we investigate two dehydrins (denoted as TsDHN-1 and TsDHN-2) from Thellungiella salsuginea. This plant is a crucifer that thrives in the Canadian sub-Arctic (Yukon Territory) where it grows on saline-rich soils and experiences periods of both extreme cold and drought. We show using circular dichroism and attenuated total reflection-Fourier transform infrared spectroscopy that ordered secondary structure is induced and stabilized in these proteins, both in free and vesicle-bound form, by association with zinc. In membrane-associated form, both proteins have an increased proportion of β-strand conformation induced by the cation, in addition to the amphipathic α-helices formed by their constituent K-segments. These results support the hypothesis that dehydrins stabilize plant plasma and organellar membranes in conditions of stress, and further that zinc may be an important co-factor in stabilization. Whereas dehydrins in the cytosol of a plant cell undergoing dehydration or temperature stress form bulk hydrogels and remain primarily disordered, dehydrins with specific membrane- or protein-associations will have induced ordered secondary structures.
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U2 - 10.1007/s00726-010-0759-0
DO - 10.1007/s00726-010-0759-0
M3 - Article
C2 - 20924623
AN - SCOPUS:80052802440
SN - 0939-4451
VL - 40
SP - 1485
EP - 1502
JO - Amino Acids
JF - Amino Acids
IS - 5
ER -