<> "The repository administrator has not yet configured an RDF license."^^ . <> . . . "Domain truncation studies reveal that the streptokinase-plasmin activator complex utilizes long range protein-protein interactions with macromolecular substrate to maximize catalytic turnover."^^ . "To explore the interdomain co-operativity during human plasminogen (HPG) activation by streptokinase (SK), we expressed the cDNAs corresponding to each SK domain individually (alpha, beta, and gamma), and also their two-domain combinations, viz. alphabeta and betagamma in Escherichia coli. After purification, alpha and beta showed activator activities of approximately 0.4 and 0.05%, respectively, as compared with that of native SK, measured in the presence of human plasmin, but the bi-domain constructs alphabeta and betagamma showed much higher co-factor activities (3.5 and 0.7% of native SK, respectively). Resonant Mirror-based binding studies showed that the single-domain constructs had significantly lower affinities for \"partner\" HPG, whereas the affinities of the two-domain constructs were remarkably native-like with regards to both binary-mode as well as ternary mode (\"substrate\") binding with HPG, suggesting that the vast difference in co-factor activity between the two- and three-domain structures did not arise merely from affinity differences between activator species and HPG. Remarkably, when the co-factor activities of the various constructs were measured with microplasminogen, the nearly 50-fold difference in the co-factor activity between the two- and three-domain SK constructs observed with full-length HPG as substrate was found to be dramatically attenuated, with all three types of constructs now exhibiting a low activity of approximately 1-2% compared to that of SK.HPN and HPG. Thus, the docking of substrate through the catalytic domain at the active site of SK-plasmin(ogen) is capable of engendering, at best, only a minimal level of co-factor activity in SK.HPN. Therefore, apart from conferring additional substrate affinity through kringle-mediated interactions, reported earlier (Dhar et al., 2002; J. Biol. Chem. 277, 13257), selective interactions between all three domains of SK and the kringle domains of substrate vastly accelerate the plasminogen activation reaction to near native levels."^^ . "2003-08-15" . . "278" . "33" . . "ASBMB"^^ . . . "The Journal of biological chemistry"^^ . . . "00219258" . . . . . . . . . . . . . . . . . . . . . . "Jayeeta"^^ . "Dhar"^^ . "Jayeeta Dhar"^^ . . "Vasudha"^^ . "Sundram"^^ . "Vasudha Sundram"^^ . . "Kammara"^^ . "Rajagopal"^^ . "Kammara Rajagopal"^^ . . "Jagpreet S"^^ . "Nanda"^^ . "Jagpreet S Nanda"^^ . . "Girish"^^ . "Sahni"^^ . "Girish Sahni"^^ . . "Anita"^^ . "Chaudhary"^^ . "Anita Chaudhary"^^ . . . . . . "Domain truncation studies reveal that the streptokinase-plasmin activator complex utilizes long range protein-protein interactions with macromolecular substrate to maximize catalytic turnover. (PDF)"^^ . . . . . "Domain truncation studies reveal that the streptokinase-plasmin activator complex utilizes long range protein-protein interactions with macromolecular substrate to maximize catalytic turnover. (Image (PNG))"^^ . . . . . . "Domain truncation studies reveal that the streptokinase-plasmin activator complex utilizes long range protein-protein interactions with macromolecular substrate to maximize catalytic turnover. (Image (PNG))"^^ . . . . . . "Domain truncation studies reveal that the streptokinase-plasmin activator complex utilizes long range protein-protein interactions with macromolecular substrate to maximize catalytic turnover. (Image (PNG))"^^ . . . . . . "Domain truncation studies reveal that the streptokinase-plasmin activator complex utilizes long range protein-protein interactions with macromolecular substrate to maximize catalytic turnover. (Image (PNG))"^^ . . . . . . "Domain truncation studies reveal that the streptokinase-plasmin activator complex utilizes long range protein-protein interactions with macromolecular substrate to maximize catalytic turnover. (Indexer Terms)"^^ . . . . . "HTML Summary of #242 \n\nDomain truncation studies reveal that the streptokinase-plasmin activator complex utilizes long range protein-protein interactions with macromolecular substrate to maximize catalytic turnover.\n\n" . "text/html" . . . "QD Chemistry"@en . .