title: Effects of segment substitution on the structure and stability of immunoglobulin G binding domain of streptococcal protein G.
abstract: Structural formation of segments plays pivotal roles in protein folding and stability, but how the segment influences the structural ensemble remains elusive. We engineered two hybrid proteins by replacing the central helical segment of immunoglobulin G binding domain of streptococcal protein G with an alpha-helix or beta(2)-strand element of a structural homologue, the immunoglobulin G binding domain of streptococcal protein L. The results show that substitution by the alpha-helical sequence retains a folded structure predominantly with a three-stranded beta-sheet but slightly destabilizes the compact ensemble, while substitution by the beta(2)-strand sequence completely destroys the structural formation. The finding implies that the local segment may influence the tertiary structure and overall stability, and the tertiary interactions may modulate structural formation of the segment, which might be considered when studying protein folding, prediction, design, and engineering.
authors.affiliation: Key Laboratory of Proteomics, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
authors.forename: Hai-Ning
authors.initials: HN
authors.lastname: Du
authors.forename: Tie-Ying
authors.initials: TY
authors.lastname: Zhang
authors.forename: Yong-Gang
authors.initials: YG
authors.lastname: Chang
authors.forename: Dong-Hai
authors.initials: DH
authors.lastname: Lin
authors.forename: Hong-Yu
authors.initials: HY
authors.lastname: Hu
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics; D008969:Molecular Sequence Data; D017510:Protein Folding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; C034284:IgG Fc-binding protein, Streptococcus; D011993:Recombinant Fusion Proteins