N-terminal half of a mitochondrial presequence peptide takes a helical conformation when bound to dodecylphosphocholine micelles: a proton nuclear magnetic resonance study |
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Authors: | T Endo I Shimada D Roise F Inagaki |
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Institution: | Department of Chemistry, College of Technology, Gunma University. |
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Abstract: | Two-dimensional proton nuclear magnetic resonance (NMR) spectra of a synthetic peptide (p25) corresponding to the amino-terminus of the yeast mitochondrial cytochrome oxidase subunit IV precursor protein have been analyzed. Sequence-specific resonance assignments of the peptide have been made in the presence of micelles of a phospholipid analog, perdeuterated dodecylphosphocholine (DPC), with the aid of such techniques as HOHAHA, DQF-COSY, and NOESY. The interresidue nuclear Overhauser effects (NOEs) indicate that the N-terminal half of p25 (S3-F11) takes a helical structure while the C-terminal half does not take a regular secondary structure. Addition of DPC to the solution of p25 induced chemical shift changes only of the resonances from the residues in the N-terminal half, suggesting that the N-terminal half of p25 is directly involved in binding to DPC. The induced helical structure in the N-terminal half at a lipid-water interface may be important in the ability of this presequence to direct a "passenger" protein into mitochondria. |
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