TY - JOUR
T1 - The structure of the catechin-binding site of human sulfotransferase 1A1
AU - Cook, Ian
AU - Wang, Ting
AU - Girvin, Mark
AU - Leyh, Thomas S.
N1 - Funding Information:
This work was supported by National Institutes of Health Grant GM10158 and Shared Instrumentation Grant 1S10OD016305.
PY - 2016/12/13
Y1 - 2016/12/13
N2 - 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 differentmolecular 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 bindingsite 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-Cysmutants 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.
AB - 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 differentmolecular 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 bindingsite 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-Cysmutants 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.
KW - Allostery
KW - Catechin
KW - Nmr
KW - Structure
KW - Sulfotransferase
UR - http://www.scopus.com/inward/record.url?scp=85005943816&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85005943816&partnerID=8YFLogxK
U2 - 10.1073/pnas.1613913113
DO - 10.1073/pnas.1613913113
M3 - Article
C2 - 27911811
AN - SCOPUS:85005943816
SN - 0027-8424
VL - 113
SP - 14312
EP - 14317
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 50
ER -