Conformational studies of the alpha-helical 28-43 fragment of the B3 domain of the immunoglobulin binding protein G from Streptococcus.
To determine whether the alpha-helix in the B3 immunoglobulin binding domain of protein G from group G Streptococcus has conformational stability as an isolated fragment, we carried out a CD and NMR study of the 16-residue peptide in solution corresponding to this alpha-helix. Based on two-dimensional H-NMR spectra recorded at three different temperatures (283, 305, and 313 K), it was found that this peptide is mostly unstructured in water at these temperatures. Weak signals corresponding to i,i+3 or i,i+4 interactions, which are characteristic of formation of turn-like structures, were observed in the ROE spectra at all temperatures. The absence of a stable three-dimensional structure of the investigated peptide supports an earlier study (Blanco and Serrano, Eur J Biochem 1995, 230, 634-649) of a possible mechanism for folding of other (B1 and B2) immunoglobulin binding domains of Protein G.
Skwierawska
Agnieszka
A
Laboratory of Biopolymer Structure, Intercollegiate Faculty of Biotechnology, University of Gdansk, Medical University of Gdańsk, Kładki 24, 80-822 Gdańsk, Poland.
Rodziewicz-Motowidło
Sylwia
S
Ołdziej
Stanisław
S
Liwo
Adam
A
Scheraga
Harold A
HA
D001426:Bacterial Proteins / Q000737:chemistry*; D002942:Circular Dichroism / Q000379:methods; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods; D017433:Protein Structure, Secondary / Q000502:physiology; D017434:Protein Structure, Tertiary / Q000502:physiology
D001426:Bacterial Proteins; C034284:IgG Fc-binding protein, Streptococcus