title: 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 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.
authors.affiliation: Dipartimento di Biochimica e Biofisica, Seconda Università degli Studi di Napoli, Via L. De Crecchio 7, 80138 Napoli, Italy.
authors.forename: Ivana
authors.initials: I
authors.lastname: Sirangelo
authors.forename: Clara
authors.initials: C
authors.lastname: Iannuzzi
authors.forename: Clorinda
authors.initials: C
authors.lastname: Malmo
authors.forename: Gaetano
authors.initials: G
authors.lastname: Irace
mesh_terms: D020106:Acrylamide / Q000737:chemistry; D019943:Amino Acid Substitution; D000818:Animals; D001059:Apoproteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D006736:Horses / Q000235:genetics / Q000378:metabolism; D007454:Iodides / Q000737:chemistry; D009211:Myoglobin / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D011487:Protein Conformation; D013050:Spectrometry, Fluorescence; D014364:Tryptophan / Q000378:metabolism*; D014907:Whales / Q000235:genetics / Q000378:metabolism
chemical_list: D001059:Apoproteins; D007454:Iodides; D009211:Myoglobin; C010857:apomyoglobin; D020106:Acrylamide; D014364:Tryptophan