title: Intermolecular interactions in staphylokinase-plasmin(ogen) bimolecular complex: function of His43 and Tyr44.
abstract: 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.
authors.affiliation: Institute of Microbial Technology (CSIR), Chandigarh, India.
authors.forename: Monika
authors.initials: M
authors.lastname: Dahiya
authors.forename: Satish
authors.initials: S
authors.lastname: Singh
authors.forename: Govindan
authors.initials: G
authors.lastname: Rajamohan
authors.forename: Deepti
authors.initials: D
authors.lastname: Sethi
authors.lastname: Ashish
authors.forename: Kanak L
authors.initials: KL
authors.lastname: Dikshit
mesh_terms: D001665:Binding Sites; D004583:Electrons; D004926:Escherichia coli / Q000201:enzymology* / Q000472:pathogenicity; D005341:Fibrinolysin / Q000737:chemistry / Q000378:metabolism*; D006639:Histidine / Q000378:metabolism; D006801:Humans; D008666:Metalloendopeptidases / Q000737:chemistry / Q000378:metabolism*; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D010958:Plasminogen / Q000378:metabolism; D011485:Protein Binding; D013379:Substrate Specificity; D014443:Tyrosine / Q000378:metabolism
chemical_list: D014443:Tyrosine; D006639:Histidine; D010958:Plasminogen; D005341:Fibrinolysin; D008666:Metalloendopeptidases; C022653:auR protein, Staphylococcus aureus