Biochemical Characterization and Tissue Distribution of Human SULT2B1

Fuda

Journal of Biological Chemistry

et al. 2003

The gene for human hydroxysteroid sulfotransferase (SULT2B1) encodes two peptides, SULT2B1a and SULT2B1b, that differ only at their amino termini. SULT2B1b has a predilection for cholesterol but is also capable of sulfonating pregnenolone, whereas SULT2B1a preferentially sulfonates pregnenolone and only minimally sulfonates cholesterol. We have determined the crystal structure of SULT2B1a and SULT2B1b bound to the substrate donor product 3 -phosphoadenosine 5 -phosphate at 2.9 and 2.4 Å, respectively, as well as SULT2B1b in the presence of the acceptor substrate pregnenolone at 2.3 Å. These structures reveal a different catalytic binding orientation for the substrate from a previously determined structure of hydroxysteroid sulfotransferase (SULT2A1) binding dehydroepiandrosterone. In addition, the amino-terminal helix comprising residues Asp 19 to Lys 26 , which determines the specificity difference between the SULT2B1 isoforms, becomes ordered upon pregnenolone binding, covering the substrate binding pocket.

supporting

confidence: 88%

Crystal Structure of Human Cholesterol Sulfotransferase (SULT2B1b) in the Presence of Pregnenolone and 3′-Phosphoadenosine 5′-Phosphate

Fuda

Journal of Biological Chemistry

et al. 2003

“…SULT2B1b also readily sulfates cholesterol (Javitt et al, 2001), and in human keratinocytes the expression of SULT2B1 was inducible by LXR activation (Jiang et al, 2005). SULT2B1b is widely expressed in human tissues, including brain, although its expression was not detectable in liver (Geese and Raftogianis, 2001;Falany et al, 2006). The regulation of SULT2B1b expression in brain tissues by LXR activation has not been described.…”

Section: Discussionmentioning

confidence: 99%

24-Hydroxycholesterol Sulfation by Human Cytosolic Sulfotransferases: Formation of Monosulfates and Disulfates, Molecular Modeling, Sulfatase Sensitivity, and Inhibition of Liver X Receptor Activation

Cook¹,

Duniec-Dmuchowski²,

Kocarek

et al. 2009

Drug Metab Dispos

ABSTRACT:24-Hydroxycholesterol (24-OHChol) is a major cholesterol metabolite and the form in which cholesterol is secreted from the brain. 24-OHChol is transported by apolipoprotein E to the liver and converted into bile acids or excreted. In both brain and liver, 24-OHChol is a liver X receptor (LXR) agonist and has an important role in cholesterol homeostasis. 24-OHChol sulfation was examined to understand its role in 24-OHChol metabolism and its effect on LXR activation. 24-OHChol was conjugated by three isoforms of human cytosolic sulfotransferase (SULT). SULT2A1 and SULT1E1 sulfated both the 3-and 24-hydroxyls to form the 24-OHChol-3, 24-disulfate. SULT2B1b formed only 24-OHChol-3-sulfate.

“…Expressed SULT2B1b demonstrates a high catalytic affinity for sulfation with 3␤-hydroxysteroids such as DHEA, pregnenolone, and androstenediol, and generally low reactivity with 3␣-hydroxysteroids and the phenolic hydroxyl of estrogens (Geese and Raftogianis, 2001;Meloche and Falany, 2001). SULT2B1b is 61% similar and 48% identical in amino acid sequence to the other member of this gene family, SULT2A1 (Meloche and Falany, 2001).…”

Section: Discussionmentioning

confidence: 99%

Characterization of Proline-Serine-Rich Carboxyl Terminus in Human Sulfotransferase 2B1b: Immunogenicity, Subcellular Localization, Kinetic Properties, and Phosphorylation

He¹,

Falany²

2006

Drug Metab Dispos

ABSTRACT:The human sulfotransferase (SULT) 2B1 gene is a member of the SULT2 gene family and encodes two isoforms, SULT2B1a and SULT2B1b. Although messages for both SULT2B1a and SULT2B1b are detectable in human tissues, only SULT2B1b has been identified immunologically. Compared with other human SULTs, SULT2B1b has an extension at the proline-and serine-rich carboxyl (PSC) end of about 53 amino acids. The structure and function of this unique PSC extension were investigated. Constructs of full-length SULT2B1b as well as truncated SULT2B1b without the PSC extension were expressed in Escherichia coli. Removal of the PSC extension significantly decreased the thermostability of the expressed enzyme as well as decreasing the rate of dehydroepiandrosterone sulfation. Rabbit polyclonal antibodies were raised against both the full-length and truncated SULT2B1b proteins. Immunoblot analysis showed that antibodies raised to fulllength SULT2B1b immunoreact only with full-length SULT2B1b, whereas antibodies raised to truncated SULT2B1b react with both full-length and truncated SULT2B1b. Unlike full-length SULT2B1b, truncated SULT2B1b was incapable of translocation to nuclei in transfected human BeWo choriocarcinoma cells. Phosphorylated serines were detected in the PSC extension of full-length SULT2B1b expressed in BeWo cells but not in truncated SULT2B1b. At least one phosphorylated serine was detected in expressed SULT2B1b via two-dimensional gel electrophoresis, immunoblot analysis, and mass spectroscopic analysis. Bacterially expressed full-length SULT2B1b but not truncated SULT2B1b was phosphorylated by casein kinase or Cdc2 protein kinase in vitro. This study suggests that the PSC extension of SULT2B1b is an important site in the immunogenicity, nuclear translocation, kinetic activity, and thermostability of this SULT isoform.