title: Aromatic-aromatic interactions in the zinc finger motif. Analysis of the two-dimensional nuclear magnetic resonance structure of a mutant domain.
abstract: The folding and stability of globular proteins are determined by a variety of chemical mechanisms, including hydrogen bonds, salt bridges and the hydrophobic effect. Of particular interest are weakly polar interactions involving aromatic rings, which are proposed to regulate the geometry of closely packed protein interiors. Such interactions reflect the electrostatic contribution of pi-electrons and, unlike van der Waals' interactions and the hydrophobic effect, may, in principle, introduce a directional force in a protein's hydrophobic core. Although the weakly polar hypothesis is supported by a statistical analysis of protein structures, the general importance of such contributions to protein folding and stability is unclear. Here, we show the presence of alternative aromatic-aromatic interactions in the two-dimensional nuclear magnetic resonance structure of a mutant Zn finger. Changes in aromatic packing lead in turn to local and non-local differences between the structures of a wild-type and mutant domain. The results provide insight into the evolution of Zn finger sequences and have implications for understanding how geometric relationships may be chemically encoded in a simple sequence template.
authors.affiliation: Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115.
authors.forename: A
authors.initials: A
authors.lastname: Jasanoff
authors.forename: M
authors.initials: M
authors.lastname: Kochoyan
authors.forename: E
authors.initials: E
authors.lastname: Fraenkel
authors.forename: J P
authors.initials: JP
authors.lastname: Lee
authors.forename: M A
authors.initials: MA
authors.lastname: Weiss
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D003196:Computer Graphics; D004247:DNA / Q000378:metabolism*; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism; D011487:Protein Conformation; D016335:Zinc Fingers / Q000235:genetics
chemical_list: D010455:Peptides; D004247:DNA