1. Structural and Mutational Analyses of the Interaction between the Barley α-Amylase/Subtilisin Inhibitor and the Subtilisin Savinase Reveal a Novel Mode of Inhibition
- Author
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Peter Rahbek Østergaard, Esben Peter Friis, Keith S. Wilson, Pernille Ollendorff Micheelsen, Michael Skjøt, Leonardo De Maria, and J. Vevodova
- Subjects
Models, Molecular ,Protein Folding ,endocrine system ,animal structures ,Trypsin inhibitor ,DNA Mutational Analysis ,Detergents ,Molecular Sequence Data ,Biology ,Crystallography, X-Ray ,Serine ,Protein structure ,Structural Biology ,Molecular Biology ,Plant Proteins ,Serine Endopeptidases ,fungi ,Subtilisin ,Hordeum ,computer.file_format ,Protein Data Bank ,Protein Structure, Tertiary ,enzymes and coenzymes (carbohydrates) ,Biochemistry ,Metals ,biological sciences ,Protein folding ,Endopeptidase K ,Trypsin Inhibitor, Kunitz Soybean ,alpha-Amylases ,computer ,Subtilisins - Abstract
Subtilisins represent a large class of microbial serine proteases. To date, there are three-dimensional structures of proteinaceous inhibitors from three families in complex with subtilisins in the Protein Data Bank. All interact with subtilisin via an exposed loop covering six interacting residues. Here we present the crystal structure of the complex between the Bacillus lentus subtilisin Savinase and the barley alpha-amylase/subtilisin inhibitor (BASI). This is the first reported structure of a cereal Kunitz-P family inhibitor in complex with a subtilisin. Structural analysis revealed that BASI inhibits Savinase in a novel way, as the interacting loop is shorter than loops previously reported. Mutational analysis showed that Thr88 is crucial for the inhibition, as it stabilises the interacting loop through intramolecular interactions with the BASI backbone.
- Published
- 2008
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