6533b82afe1ef96bd128b635

RESEARCH PRODUCT

Site-Specific Information on Membrane Protein Folding by Electron Spin Echo Envelope Modulation Spectroscopy

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description

Compared to folding of soluble proteins, folding of membrane proteins is complicated by the fact that it requires an amphiphilic environment. Few existing techniques can provide structurally resolved information on folding kinetics. For the major plant light harvesting complex LHCII, it is demonstrated that changes in water accessibility of a particular amino acid residue can be followed during folding by measuring the hyperfine interaction of spin labels with deuterium nuclei of heavy water. The incorporation of residue 196 into the hydrophobic core of a detergent micelle was investigated. The technique provides a time constant that is similar to the one found with fluorescence spectroscopy for the slower folding step of the whole protein and with electron paramagnetic resonance for change of the distance between residues 90 and 196. If applied to several residues, this technique should provide information on the sequence of events during membrane protein folding.