title: Restored heptad pattern continuity does not alter the folding of a four-alpha-helix bundle.
abstract: The sequences of alpha-helical coiled-coils and bundles are characterized by a specific pattern of hydrophobic and hydrophilic residues which is repeated every seven residues. Highly conserved breaks in this pattern frequently occur in segments of otherwise continuous heptad substructures. The hairpin bend of the ROP protein coincides with such a break and provides a model system for the study of the structural effects induced by heptad discontinuities. The structure of a ROP mutant which re-establishes a continuous heptad pattern, shows insignificant changes relative to the wild-type protein, as is also reflected in its conformational stability, spectroscopic properties and unfolding behaviour. Thus, formation of alpha-alpha-hairpin bends may occur both in the presence and absence of heptad breaks.
authors.affiliation: University of Crete, Dept. of Biology, Heraklion, Greece.
authors.forename: M
authors.initials: M
authors.lastname: Vlassi
authors.forename: C
authors.initials: C
authors.lastname: Steif
authors.forename: P
authors.initials: P
authors.lastname: Weber
authors.forename: D
authors.initials: D
authors.lastname: Tsernoglou
authors.forename: K S
authors.initials: KS
authors.lastname: Wilson
authors.forename: H J
authors.initials: HJ
authors.lastname: Hinz
authors.forename: M
authors.initials: M
authors.lastname: Kokkinidis
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D002942:Circular Dichroism; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017510:Protein Folding; D016601:RNA-Binding Proteins / Q000737:chemistry*; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
chemical_list: D001426:Bacterial Proteins; D016601:RNA-Binding Proteins; C054243:Rop protein, ColE1 plasmid; D014867:Water