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Intermolecular interactions in staphylokinase–plasmin(ogen) bimolecular complex: Function of His43 and Tyr44
Author(s) -
Dahiya Monika,
Singh Satish,
Rajamohan Govindan,
Sethi Deepti,
Dikshit Kanak L.
Publication year - 2011
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2011.04.030
Subject(s) - staphylokinase , chemistry , plasmin , intermolecular force , activator (genetics) , intermolecular interaction , plasminogen activator , residue (chemistry) , site directed mutagenesis , stereochemistry , mutagenesis , biochemistry , biophysics , mutant , enzyme , recombinant dna , molecule , biology , receptor , gene , organic chemistry , genetics
Staphylokinase (SAK) forms a 1:1 stoichiometric complex with human plasmin (Pm) and switches its substrate specificity to generate a plasminogen (Pg) activator complex. Site‐directed mutagenesis of SAKHis43 and SAKTyr44 demonstrated the crucial requirement of a positively charged and an aromatic residue, respectively, at these positions for optimal functioning of SAK–Pm activator complex. Molecular modeling studies further revealed the role of these residues in making cation–pi and pi–pi interactions with Trp215 of Pm and thus establishing the crucial intermolecular contacts within the active site cleft of the activator complex for the cofactor activity of SAK.