Location of helical regions in tetrapyrrole-containing proteins by a helical hydrophobic moment analysis. Application to phytochrome.


Journal Article

Helical regions in many tetrapyrrole proteins are highly amphiphilic, one side interacting with a hydrophobic core and another side interacting with the polar solvent. The mean helical hydrophobic moment is a measure of amphiphilicity of a helix. Helical regions in myoglobin, the alpha and beta subunits of C-phycocyanin, and cytochrome c can be distinguished from nonhelical regions by use of a hydrophobic moment analysis. 24 of 27 (89%) of the helical regions in these proteins were located by this analysis. Calculations were also performed on chymotrypsin, ribonuclease, and papain, which do not possess as pronounced a hydrophobic core as the tetrapyrrole-containing proteins. Less than 50% of the helical regions were correctly located, indicating a lack of amphiphilicity in the helices of these proteins. The hydrophobic moment analysis was also used to predict helical regions in phytochrome, the ubiquitous photoreceptor in plants. Additionally, this analysis is used to quickly locate internal hydrophilic residues which may be functionally important. The distribution of hydrophobic moments from a random sequence was determined so that qualitative and to some extent quantitative comparisons between different amphiphilic helices may be made.

Full Text

Duke Authors

Cited Authors

  • Parker, W; Song, PS

Published Date

  • October 15, 1990

Published In

Volume / Issue

  • 265 / 29

Start / End Page

  • 17568 - 17575

PubMed ID

  • 2170385

Pubmed Central ID

  • 2170385

International Standard Serial Number (ISSN)

  • 0021-9258


  • eng

Conference Location

  • United States