title: What makes a protein a protein? Hydrophobic core designs that specify stability and structural properties.
abstract: Here we describe how the systematic redesign of a protein's hydrophobic core alters its structure and stability. We have repacked the hydrophobic core of the four-helix-bundle protein, Rop, with altered packing patterns and various side chain shapes and sizes. Several designs reproduce the structure and native-like properties of the wild-type, while increasing the thermal stability. Other designs, either with similar sizes but different shapes, or with decreased sizes of the packing residues, destabilize the protein. Finally, overpacking the core with the larger side chains causes a loss of native-like structure. These results allow us to further define the roles of tight residue packing and the burial of hydrophobic surface area in the construction of native-like proteins.
authors.affiliation: Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA.
authors.forename: M
authors.initials: M
authors.lastname: Munson
authors.forename: S
authors.initials: S
authors.lastname: Balasubramanian
authors.forename: K G
authors.initials: KG
authors.lastname: Fleming
authors.forename: A D
authors.initials: AD
authors.lastname: Nagi
authors.forename: R
authors.initials: R
authors.lastname: O'Brien
authors.forename: J M
authors.initials: JM
authors.lastname: Sturtevant
authors.forename: L
authors.initials: L
authors.lastname: Regan
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D002152:Calorimetry, Differential Scanning; D002942:Circular Dichroism; D019791:Guanidine; D006146:Guanidines / Q000737:chemistry; D006358:Hot Temperature; D009682:Magnetic Resonance Spectroscopy; D009154:Mutation; D011485:Protein Binding; D011487:Protein Conformation; D011489:Protein Denaturation; D016601:RNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013329:Structure-Activity Relationship; D013816:Thermodynamics; D014461:Ultracentrifugation
chemical_list: D001426:Bacterial Proteins; D006146:Guanidines; D016601:RNA-Binding Proteins; D011994:Recombinant Proteins; C054243:Rop protein, ColE1 plasmid; D019791:Guanidine