Phenylalanine90 and phenylalanine93 are crucial amino acids within the estrogen binding site of the human UDP-glucuronosyltransferase 1A10

Athena Davenport, Yan Xiong, Stacie Bratton, Anna Gallus-Zawada, Moshe Finel, Anna Radominska-Pandya

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

Human UDP-glucuronosyltransferase 1A10 has been identified as the major isoform involved in the biotransformation of a wide range of phenolic substrates, including native estrogens and their oxidized metabolites. Our recent studies point to the F90-M91-V92-F93 amino acid motif of UGT1A10, which was identified using photoaffinity labeling followed by LC-MS/MS analysis, as a key determinant of the binding of phenolic substrates. In this report, we have evaluated the role of F90, V92, and F93 in the recognition of estrogens by UGT1A10 using site-directed mutagenesis. Kinetic studies using five mutants revealed that F90 and F93 are critical residues for the recognition of all estrogen substrates. The substitution of F90 with alanine totally abolished the activity of this enzyme toward all the estrogens investigated. Overall, sequential removal for the aromatic ring (F to L) and of the hydrophobic chain (F to A and V to A) from amino acids 90, 92, and 93 effectively alters estrogen recognition. This demonstrates that individual features of the native and hydroxylated estrogens determine the specific binding properties of the compound within the binding site of the human UGT1A10 and the mutants. The resulting activities are completely abolished, unchanged, increased, or decreased depending on the structures of both the mutant and the substrate. The novel identification of UGT1A10 as the major isoform involved in the glucuronidation of all estrogens and the discovery of the importance of the FMVF motif in the binding of steroids will help to elucidate the molecular mechanism of glucuronidation, resulting in the design of more effective estrogen-based therapies.

Original languageEnglish (US)
Pages (from-to)85-94
Number of pages10
JournalSteroids
Volume72
Issue number1
DOIs
StatePublished - Jan 1 2007

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Estrogens
Binding Sites
Amino Acids
Substrates
Protein Isoforms
Mutagenesis
Amino Acid Motifs
bilirubin uridine-diphosphoglucuronosyl transferase 1A10
Biotransformation
Metabolites
Site-Directed Mutagenesis
Alanine
Labeling
Substitution reactions
Steroids
Kinetics
Enzymes

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology
  • Endocrinology
  • Pharmacology
  • Clinical Biochemistry
  • Organic Chemistry

Cite this

Phenylalanine90 and phenylalanine93 are crucial amino acids within the estrogen binding site of the human UDP-glucuronosyltransferase 1A10. / Davenport, Athena; Xiong, Yan; Bratton, Stacie; Gallus-Zawada, Anna; Finel, Moshe; Radominska-Pandya, Anna.

In: Steroids, Vol. 72, No. 1, 01.01.2007, p. 85-94.

Research output: Contribution to journalArticle

Davenport, Athena ; Xiong, Yan ; Bratton, Stacie ; Gallus-Zawada, Anna ; Finel, Moshe ; Radominska-Pandya, Anna. / Phenylalanine90 and phenylalanine93 are crucial amino acids within the estrogen binding site of the human UDP-glucuronosyltransferase 1A10. In: Steroids. 2007 ; Vol. 72, No. 1. pp. 85-94.
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