A heterodimer of human 3'-phospho-adenosine-5'-phosphosulphate (PAPS) synthases is a new sulphate activating complex

Research output: Contribution to journalArticlepeer-review

Authors

  • Daniel Grum
  • Johannes van den Boom
  • Daniel Neumann
  • Anja Matena
  • Nina M Link

Abstract

3'-Phospho-adenosine-5'-phosphosulphate (PAPS) synthases are fundamental to mammalian sulphate metabolism. These enzymes have recently been linked to a rising number of human diseases. Despite many studies, it is not yet understood how the mammalian PAPS synthases 1 and 2 interact with each other. We provide first evidence for heterodimerisation of these two enzymes by pull-down assays and Förster resonance energy transfer (FRET) measurements. Kinetics of dimer dissociation/association indicates that these heterodimers form as soon as PAPSS1 and -S2 encounter each other in solution. Affinity of the homo- and heterodimers were found to be in the low nanomolar range using anisotropy measurements employing proteins labelled with the fluorescent dye IAEDANS that--in spite of its low quantum yield--is well suited for anisotropy due to its large Stokes shift. Within its kinase domain, the PAPS synthase heterodimer displays similar substrate inhibition by adenosine-5'-phosphosulphate (APS) as the homodimers. Due to divergent catalytic efficacies of PAPSS1 and -S2, the heterodimer might be a way of regulating PAPS synthase function within mammalian cells.

Details

Original languageEnglish
Pages (from-to)420-5
Number of pages6
JournalBiochemical and Biophysical Research Communications
Volume395
Issue number3
Publication statusPublished - 7 May 2010

Keywords

  • Anisotropy, Enzyme Activation, Humans, Isoenzymes, Kinetics, Multienzyme Complexes, Protein Multimerization, Sulfate Adenylyltransferase, Sulfates