The structure of the catechin-binding site of human sulfotransferase 1A1
Autor: | Ting Wang, Ian Cook, Thomas S. Leyh, Mark E. Girvin |
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Rok vydání: | 2016 |
Předmět: |
Models
Molecular 0301 basic medicine Sulfotransferase Stereochemistry Allosteric regulation Sulfotransferase 1A1 Molecular Dynamics Simulation Catechin Substrate Specificity 03 medical and health sciences Humans Nuclear Magnetic Resonance Biomolecular chemistry.chemical_classification Multidisciplinary 030102 biochemistry & molecular biology biology Chemistry Biological Sciences Arylsulfotransferase Catechin binding Small molecule Recombinant Proteins Isoenzymes Molecular Docking Simulation Kinetics 030104 developmental biology Enzyme Allosteric enzyme Docking (molecular) Mutagenesis Site-Directed biology.protein Spin Labels Allosteric Site Protein Binding |
Zdroj: | Proceedings of the National Academy of Sciences. 113:14312-14317 |
ISSN: | 1091-6490 0027-8424 |
Popis: | We are just beginning to understand the allosteric regulation of the human cytosolic sulfotransferase (SULTs) family-13 disease-relevant enzymes that regulate the activities of hundreds, if not thousands, of signaling small molecules. SULT1A1, the predominant isoform in adult liver, harbors two noninteracting allosteric sites, each of which binds a different molecular family: the catechins (naturally occurring flavonols) and nonsteroidal antiinflammatory drugs (NSAIDs). Here, we present the structure of an SULT allosteric binding site-the catechin-binding site of SULT1A1 bound to epigallocatechin gallate (EGCG). The allosteric pocket resides in a dynamic region of the protein that enables EGCG to control opening and closure of the enzyme's active-site cap. Furthermore, the structure offers a molecular explanation for the isozyme specificity of EGCG, which is corroborated experimentally. The binding-site structure was obtained without X-ray crystallography or multidimensional NMR. Instead, a SULT1A1 apoprotein structure was used to guide positioning of a small number of spin-labeled single-Cys mutants that coat the entire enzyme surface with a paramagnetic field of sufficient strength to determine its contribution to the bound ligand's transverse (T2) relaxation from its 1D solution spectrum. EGCG protons were mapped to the protein surface by triangulation using the T2 values to calculate their distances to a trio of spin-labeled Cys mutants. The final structure was obtained using distance-constrained molecular dynamics docking. This approach, which is readily extensible to other systems, is applicable over a wide range of ligand affinities, requires little protein, avoids the need for isotopically labeled protein, and has no protein molecular weight limitations. |
Databáze: | OpenAIRE |
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