Recombinant SEC14-like proteins (TAP) possess GTPase activity

Biochem Biophys Res Commun. 2005 Jan 7;326(1):254-9. doi: 10.1016/j.bbrc.2004.11.021.

Abstract

The three human SEC14-like proteins TAP1, TAP2, and TAP3 were expressed in Escherichia coli and purified by means of an amino-terminal His-tag. The recombinant TAP proteins bound alpha-, beta-, gamma-, and delta-tocopherol, certain phospholipids, and squalene. Intriguingly, the TAP proteins showed considerable GTPase activity that was comparable to that of small GTP-binding proteins of the Rab family. Although the TAP proteins contain important motifs to provide GTPase activity, the surrounding secondary structure markedly differed from common G-protein domains. However, these motifs are located in close proximity in the TAP structure and may therefore form an active site for GTP-binding and hydrolysis.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATP Binding Cassette Transporter, Subfamily B, Member 2
  • ATP Binding Cassette Transporter, Subfamily B, Member 3
  • ATP-Binding Cassette Transporters / chemistry*
  • ATP-Binding Cassette Transporters / genetics
  • ATP-Binding Cassette Transporters / metabolism
  • Amino Acid Sequence
  • Binding Sites
  • Carrier Proteins / chemistry*
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism
  • Enzyme Activation
  • Escherichia coli / enzymology
  • Escherichia coli / genetics
  • GTP Phosphohydrolases / chemistry*
  • Humans
  • Models, Molecular*
  • Molecular Sequence Data
  • Peptide Fragments / chemistry*
  • Peptide Fragments / genetics
  • Peptide Fragments / metabolism
  • Protein Binding
  • Protein Precursors / chemistry*
  • Protein Precursors / genetics
  • Protein Precursors / metabolism
  • Recombinant Proteins / analysis
  • Recombinant Proteins / chemistry*
  • Recombinant Proteins / metabolism
  • Sequence Homology, Amino Acid
  • Structure-Activity Relationship
  • Substrate Specificity

Substances

  • ATP Binding Cassette Transporter, Subfamily B, Member 2
  • ATP Binding Cassette Transporter, Subfamily B, Member 3
  • ATP-Binding Cassette Transporters
  • Carrier Proteins
  • Peptide Fragments
  • Protein Precursors
  • Recombinant Proteins
  • SEC14L1 protein, human
  • TAP1 protein, human
  • thyrotropin-releasing hormone-associated peptide 3, human
  • TAP2 protein, human
  • GTP Phosphohydrolases