Tryptophanyl substitutions in apomyoglobin affect conformation and dynamic properties of AGH subdomain

Abstract The solvent accessibilities to the tryptophanyl microenvironments of wild type sperm whale apomyoglobin (apoMb) and two mutants (W7F and W14F) containing a single tryptophan are measured by fluorescence quenching studies. The results are compared to those relative to horse apoMb. In the wil...

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Bibliographic Details
Published in:Biopolymers
Main Authors: Sirangelo, Ivana, Iannuzzi, Clara, Malmo, Clorinda, Irace, Gaetano
Format: Article in Journal/Newspaper
Language:English
Published: Wiley 2003
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Online Access:http://dx.doi.org/10.1002/bip.10503
https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fbip.10503
https://onlinelibrary.wiley.com/doi/pdf/10.1002/bip.10503
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Summary:Abstract The solvent accessibilities to the tryptophanyl microenvironments of wild type sperm whale apomyoglobin (apoMb) and two mutants (W7F and W14F) containing a single tryptophan are measured by fluorescence quenching studies. The results are compared to those relative to horse apoMb. In the wild type sperm whale protein, no difference is noticed in the solvent accessibility of the two indole residues, as documented by the values of the Stern–Volmer constants. By contrast, the two tryptophan residues of horse apoMb are exposed to the solvent in a different way, thus indicating that some local conformational differences exist between the two homologous proteins in solution. The single W → F substitution at either position 7 or 14 determines local conformational changes that increase the accessibility of the remaining indole residue but do not affect the overall architecture of the protein molecule. © 2003 Wiley Periodicals, Inc. Biopolymers (Biospectroscopy) 70:649–654, 2003