Mechanism of formation of the C-terminal beta-hairpin of the B3 domain of the immunoglobulin binding protein G from Streptococcus. II. Interplay of local backbone conformational dynamics and long-range hydrophobic interactions in hairpin formation.
Two peptides, corresponding to the turn region of the C-terminal beta-hairpin of the B3 domain of the immunoglobulin binding protein G from Streptococcus, consisting of residues 51-56 [IG(51-56)] and 50-57 [IG(50-57)], respectively, were studied by circular dichroism and NMR spectroscopy at various temperatures and by differential scanning calorimetry. Our results show that the part of the sequence corresponding to the beta-turn in the native structure (DDATKT) of the B3 domain forms bent conformations similar to those observed in the native protein. The formation of a turn is observed for both peptides in a broad range of temperatures (T = 283-323 K), which confirms the conclusion drawn from our previous studies of longer sequences from the C-terminal beta-hairpin of the B3 domain of the immunoglobulin binding protein G (16, 14, and 12 residues), that the DDATKT sequence forms a nucleation site for formation of the beta-hairpin structure of peptides corresponding to the C-terminal part of all the B domains of the immunoglobulin binding protein G. We also show and discuss the role of long-range hydrophobic interactions as well as local conformational properties of polypeptide chains in the mechanism of formation of the beta-hairpin structure.
Skwierawska
Agnieszka
A
Medical University of Gdańsk, Poland.
Zmudzińska
Wioletta
W
Ołdziej
Stanisław
S
Liwo
Adam
A
Scheraga
Harold A
HA
D002942:Circular Dichroism; D057927:Hydrophobic and Hydrophilic Interactions; D007136:Immunoglobulins / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D009419:Nerve Tissue Proteins / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry* / Q000378:metabolism*; D011485:Protein Binding; D017433:Protein Structure, Secondary; D013291:Streptococcus / Q000378:metabolism
C029152:G-substrate; D007136:Immunoglobulins; D009419:Nerve Tissue Proteins; D010455:Peptides