title: Secondary structure of streptokinase in aqueous solution: a Fourier transform infrared spectroscopic study.
abstract: The secondary structure of streptokinase (Sk) in aqueous solution was quantitatively examined by using Fourier transform infrared (FT-IR) spectroscopy. Resolution enhancement techniques, including Fourier deconvolution and derivative spectroscopy, were combined with band curve-fitting procedures to quantitate the spectral information from the amide I bands. Nine component bands were found under the broad, nearly featureless amide I bands which reflect the presence of various substructures. The relative areas of these component bands indicate an amount of beta-sheet between 30 and 37% and an alpha-helix content of only 12-13% in Sk. Further conformational substructures are assigned to turns (25-26%) and to "random" structures (15-16%). Additionally, the correlation of a pronounced component band near 1640 cm-1 (10-16% fractional area) with the possible presence of 3(10)-helices is discussed.
authors.affiliation: Max Delbrück Center for Molecular Medicine, Berlin-Buch, FRG.
authors.forename: H
authors.initials: H
authors.lastname: Fabian
authors.forename: D
authors.initials: D
authors.lastname: Naumann
authors.forename: R
authors.initials: R
authors.lastname: Misselwitz
authors.forename: O
authors.initials: O
authors.lastname: Ristau
authors.forename: D
authors.initials: D
authors.lastname: Gerlach
authors.forename: H
authors.initials: H
authors.lastname: Welfle
mesh_terms: D000577:Amides; D003903:Deuterium; D005583:Fourier Analysis; D006860:Hydrogen Bonding; D011487:Protein Conformation; D013055:Spectrophotometry, Infrared; D013300:Streptokinase / Q000648:ultrastructure*; D014867:Water
chemical_list: D000577:Amides; D014867:Water; D003903:Deuterium; D013300:Streptokinase