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Conformation and stability of streptokinases from nephritogenic and nonnephritogenic strains of streptococci
Author(s) -
Welfle K.,
Misselwitz R.,
Schaup A.,
Gerlach D.,
Welfle H.
Publication year - 1997
Publication title -
proteins: structure, function, and bioinformatics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.699
H-Index - 191
eISSN - 1097-0134
pISSN - 0887-3585
DOI - 10.1002/(sici)1097-0134(199701)27:1<26::aid-prot4>3.0.co;2-l
Subject(s) - microbiology and biotechnology , biology
Abstract Conformation and stability of three Sks from Streptococcus equisimilis strain H46A, Streptococcus pyogenes strain A374, and Streptococcus pyogenes strain AT27 were compared by limited proteolysis, CD, and fluorescence measurements and by DSC. The general similarity of the peptide CD spectra in the spectral region 185 to 260 nm indicates the same type of folding for the three proteins. Fluorescence and aromatic CD spectra are consistent with a predominant surface localization of the aromatic amino acids and a low rigidity of their surroundings. A major difference among the three Sks is shown by deconvolution of their excessive heat capacity functions. Deconvolution reveals two energetic folding units in Sk H46A but three energetic folding units in Sk A374 and Sk AT27. Digestion of the Sks with trypsin indicates a reduced sensitivity of the C‐terminal region of Sk A374 and Sk AT27 in comparison to Sk H46A. This suggests that amino acids of the C‐terminal region participate in the formation of the third folding unit of Sk A374 and Sk AT27. Proteins 27:26–35 © 1997 Wiley‐Liss, Inc.