N-terminal domain of Avena phytochrome: interactions with sodium dodecyl sulfate micelles and N-terminal chain truncated phytochrome.

Journal Article

Phytochrome is the ubiquitous red light photoreceptor present in plants. Properties of the 6-kDa end terminal region of phytochrome A (PHYA from etiolated Avena) have been investigated by the use of synthetic polypeptide fragments corresponding to that region. This region of the phytochrome A protein has been viewed as a possible functional site due to the large differences in the sequence's conformation and exposure between the Pr (red light-absorbing form) and Pfr (far-red light-absorbing, gene-regulating form) species of phytochrome A. Hydrophobic moment calculations reveal amphiphilic helical potential in this section of the protein, consistent with the folding of the N-terminal region onto a hydrophobic chromophore/chromophore pocket. A large N-terminal synthetic peptide also demonstrated helical folding in the presence of SDS micelles. This experimental evidence indicates that the N-terminal alpha-helical folding upon conversion of the regulatorily inactive Pr to the active Pfr form of phytochrome A is likely driven at least in part by amphiphilic helix stabilization. Further, the large synthetic peptide was spectrally demonstrated to interact with phytochrome A lacking the N-terminal region. The formation of this nativelike complex may provide us with a tool for both biophysical and physiological studies on the mechanism of phytochrome A signal transduction.

Full Text

Duke Authors

Cited Authors

  • Parker, W; Partis, M; Song, PS

Published Date

  • October 6, 1992

Published In

Volume / Issue

  • 31 / 39

Start / End Page

  • 9413 - 9420

PubMed ID

  • 1390724

International Standard Serial Number (ISSN)

  • 0006-2960

Language

  • eng

Conference Location

  • United States