Mechanism of formation of the C‐terminal β‐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 |
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Authors: | Agnieszka Skwierawska Wioletta Żmudzińska Stanisław Ołdziej Adam Liwo Harold A. Scheraga |
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Affiliation: | 1. Laboratory of Biopolymer Structure, Intercollegiate Faculty of Biotechology, University of Gdańsk, Medical University of Gdańsk, K?adki 24, 80‐822 Gdańsk, Poland;2. Baker Laboratory of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853‐1301;3. Faculty of Chemistry, University of Gdańsk, Sobieskiego 18, 80‐952 Gdańsk, Poland |
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Abstract: | Two peptides, corresponding to the turn region of the C‐terminal β‐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 β‐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 β‐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 β‐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 β‐hairpin structure. Proteins 2009. © 2009 Wiley‐Liss, Inc. |
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Keywords: | peptide structure β ‐hairpin B3 domain of protein G NMR CD |
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