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Characterization of Lys-698-to-Met substitution in human plasminogen catalytic domain.
- Source :
-
Proteins [Proteins] 2004 Aug 01; Vol. 56 (2), pp. 277-84. - Publication Year :
- 2004
-
Abstract
- Streptokinase (SK) is a human plasminogen (Pg) activator secreted by streptococci. The activation mechanism of SK differs from that of physiological Pg activators in that SK is not a protease and cannot proteolytically activate Pg. Instead, it forms a tight complex with Pg that proteolytically activates other Pg molecules. The residue Lys-698 of human Pg was hypothesized to participate in triggering activation in the SK-Pg complex. Here, we report a study of the Lys-698 to Met substitution in the catalytic domain of Pg (microPg) containing the proteolytic activation-resistant background (R561A). While it remains competent in forming a complex with SK, maintaining a comparable equilibration dissociation constant (K(D)), the recombinant protein shows a nearly 60-fold reduction in amidolytic activity relative to its R561A background when mixed with native SK. A 2.3 A crystal structure of this mutant microPg confirmed the correct folding of this recombinant protein. Combined with other biochemical data, these results support the premise that Lys-698 of human Pg plays a functional role in the so-called N-terminal insertion activation mechanism by SK.<br /> (Copyright 2004 Wiley-Liss, Inc.)
- Subjects :
- Amino Acid Substitution
Binding Sites
Catalysis
Chromogenic Compounds metabolism
Crystallography, X-Ray
Enzyme Activation drug effects
Humans
Lysine chemistry
Macromolecular Substances
Methionine chemistry
Models, Molecular
Molecular Sequence Data
Mutation, Missense
Plasminogen metabolism
Pliability
Protein Binding
Protein Conformation
Protein Folding
Protein Interaction Mapping
Protein Structure, Tertiary
Recombinant Fusion Proteins chemistry
Recombinant Fusion Proteins metabolism
Streptokinase metabolism
Streptokinase pharmacology
Structure-Activity Relationship
Surface Plasmon Resonance
Plasminogen chemistry
Subjects
Details
- Language :
- English
- ISSN :
- 1097-0134
- Volume :
- 56
- Issue :
- 2
- Database :
- MEDLINE
- Journal :
- Proteins
- Publication Type :
- Academic Journal
- Accession number :
- 15211511
- Full Text :
- https://doi.org/10.1002/prot.20070