<> "The repository administrator has not yet configured an RDF license."^^ . <> . . . "Role of the 88-97 loop in plasminogen activation by streptokinase probed through site-specific mutagenesis."^^ . "The role of a prominent surface-exposed loop (residues 88-97) in the alpha domain of streptokinase (SK), in human plasminogen (HPG) activation was explored through its selective mutagenesis and deletion studies. We first made a conformationally constrained derivative of the loop by the substitution of sequences known to possess a strong propensity for beta-turn formation. The mutant so formed (termed SK88-97-Beta Turn), when tested for co-factor activity against substrate HPG, after first forming a 1:1 molar complex with human plasmin (HPN), showed a nearly 6-fold decreased co-factor activity compared to the wild-type, native SK. The major catalytic change was observed to be at the k(cat) level, with relatively minor changes in Km values against HPG. Real-time binary interaction (i.e. the 1:1 complexation between SK, or its mutant/s, with HPG), and ternary complexation studies (i.e. the docking of a substrate HPG molecule into the preformed SK-HPG complex) using Surface Plasmon Resonance were done. These studies revealed minor alterations in binary complex formation but the ternary interactions of the substitution and/or deletion mutants were found to be decreased for full-length HPG compared to that for native SK.HPG. In contrast, their ternary interactions with the isolated five-kringle domain unit of plasminogen (K1-5) showed Kd values comparable to that seen with the native SK.HPG complex. Taking into consideration the overall alterations observed in catalytic levels after site-specific mutagenesis and complete loop deletion of the 88-97 loop, on the one hand, and its known position at the SK-HPG interface in the binary complex, suggests the importance of this loop. The present results suggest that the 88-97 loop of the alpha domain of SK contributes towards catalytic turn-over, even though its individual contribution towards enzyme-substrate affinity per se is minimal."^^ . "2008-09" . . "1784" . "9" . . "Elsevier Science"^^ . . . "Biochimica et biophysica acta"^^ . . . "00063002" . . . . . . . . . . . . . . . . "Balvinder"^^ . "Singh"^^ . "Balvinder Singh"^^ . . "Manish"^^ . "Datt"^^ . "Manish Datt"^^ . . "Girish"^^ . "Sahni"^^ . "Girish Sahni"^^ . . "Suman"^^ . "Yadav"^^ . "Suman Yadav"^^ . . . . . . "Role of the 88-97 loop in plasminogen activation by streptokinase probed through site-specific mutagenesis. (PDF)"^^ . . . . . "Role of the 88-97 loop in plasminogen activation by streptokinase probed through site-specific mutagenesis. (Indexer Terms)"^^ . . . . . . "Role of the 88-97 loop in plasminogen activation by streptokinase probed through site-specific mutagenesis. (Image (PNG))"^^ . . . . . . "Role of the 88-97 loop in plasminogen activation by streptokinase probed through site-specific mutagenesis. (Image (PNG))"^^ . . . . . . "Role of the 88-97 loop in plasminogen activation by streptokinase probed through site-specific mutagenesis. (Image (PNG))"^^ . . . . . . "Role of the 88-97 loop in plasminogen activation by streptokinase probed through site-specific mutagenesis. (Image (PNG))"^^ . . . . . "HTML Summary of #1071 \n\nRole of the 88-97 loop in plasminogen activation by streptokinase probed through site-specific mutagenesis.\n\n" . "text/html" . . . "QR Microbiology"@en . .