Fluctuation and rotation of human growth hormone-releasing factor in the presence and the absence of phospholipid bilayer analyzed by time-resolved fluorescence depolarization.
Time-resolved fluorescence depolarization measurements were carried out for human growth hormone-releasing factor analog ([Trp10]-hGRF (1-29) NH2), where the Trp10 residue was incorporated as a fluorescent probe, in the presence and the absence of 1,2-dimyristoyl-sn-glycero-3-phospho-rac- glycerol(DMPG) liposome and in aqueous 2,2,2-trifluoroethanol (TFE) solution. The fluorescence lifetimes and the rotatory correlation times of the peptide in each medium were determined. The apparent volumes of the rotatory Brownian motion unit calculated from these fluorescent parameters indicate the different mode of the fluctuation and/or the rotation of the peptide in each medium, such as: (i) In the aqueous solution, several segments of the peptide fluctuate individually. (ii) In the DMPG bilayer, both the local fluctuation of Trp residue alone and the rotation of the whole molecule exist. (iii) In the aqueous TFE solution, the monomeric peptide rotates as a rigid ellipsoid.
Honda
S
S
Research Institute for Polymers and Textiles, Tsukuba, Japan.
Morii
H
H
Ohashi
S
S
Uedaira
H
H
D000595:Amino Acid Sequence; D002942:Circular Dichroism; D005454:Fluorescence Polarization; D005456:Fluorescent Dyes; D013007:Growth Hormone-Releasing Hormone / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008051:Lipid Bilayers; D008433:Mathematics; D008969:Molecular Sequence Data; D010715:Phosphatidylglycerols; D010743:Phospholipids / Q000378:metabolism*; D011487:Protein Conformation; D014364:Tryptophan
D005456:Fluorescent Dyes; D008051:Lipid Bilayers; D010715:Phosphatidylglycerols; D010743:Phospholipids; D014364:Tryptophan; D013007:Growth Hormone-Releasing Hormone; C002773:dimyristoylphosphatidylglycerol