Title

Highly restricted distributions of hydrophobic and charged amino acids in longitudinal quadrants of alpha-helices

UMMS Affiliation

Department of Pharmacology; Program in Molecular Medicine

Publication Date

3-25-1991

Document Type

Article

Subjects

*Amino Acids; *Protein Conformation

Disciplines

Life Sciences | Medicine and Health Sciences

Abstract

Helix formation in folding proteins is stabilized by binding of recurrent hydrophobic side chains in one longitudinal quadrant against the locally most hydrophobic region of the protein. To test this hypothesis, we fitted sequences of 247 alpha-helices of 55 proteins to the circular (infinite) template (symbol; see text) to maximize the strip-of-helix hydrophobicity index (the mean hydrophobicity of residues in (symbol; see text) positions). These template-predicted configurations closely matched crystallographic structures in 87% of four- or five-turn helices compared. We determined the longitudinal quadrant distributions of amino acids in the template-fitted, sheet projections of alpha-helices with respect to the best longitudinal, hydrophobic strip on each helix and to the N and C termini, interiors, and entire helices. Amino acids Leu, Ile, Val, and Phe were concentrated in one longitudinal quadrant (p less than 0.001). Lys, Arg, Asp, and Glu were not in the quadrant of Leu, Ile, Val, and Phe (p less than 0.001). Significant quadrant distributions for other amino acids and for termini of the helices were also found.

Rights and Permissions

Citation: J Biol Chem. 1991 Mar 25;266(9):5521-4.

Related Resources

Link to Article in PubMed

Journal/Book/Conference Title

The Journal of biological chemistry

PubMed ID

2005094