title: Crystal structure of streptokinase beta-domain.
abstract: Streptokinase, a 47 kDa secreted protein of hemolytic strains of streptococci, is a human plasminogen activator and contains three structural domains linked by flexible loops. We describe here the crystal structure of the isolated streptokinase middle (SKbeta) domain determined at 2.4 A resolution. Among the functionally important structural features is a putative binding site for a kringle domain of plasminogen located at the tip of a fully exposed hairpin loop. The distribution of genetically conserved residues of SKbeta is strongly correlated with their functions. The extensive interface of the SKbeta dimer suggests that such dimers may also exist in solution for free SKbeta.
authors.affiliation: Crystallography Program, Oklahoma Medical Research Foundation, 825 N. E. 13th Street, Oklahoma City, OK 73104, USA.
authors.forename: X
authors.initials: X
authors.lastname: Wang
authors.forename: J
authors.initials: J
authors.lastname: Tang
authors.forename: B
authors.initials: B
authors.lastname: Hunter
authors.forename: X C
authors.initials: XC
authors.lastname: Zhang
mesh_terms: D000595:Amino Acid Sequence; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid; D013291:Streptococcus / Q000737:chemistry* / Q000201:enzymology / Q000235:genetics; D013300:Streptokinase / Q000737:chemistry* / Q000235:genetics
chemical_list: D013300:Streptokinase