A unique lipoylation system in the Archaea: lipoylation in Thermoplasma acidophilum requires two proteins

Mareike G. Posner, Abhishek Upadhyay, Stefan Bagby, David W. Hough, Michael J. Danson

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

Members of the 2-oxoacid dehydrogenase multienzyme complex family play a key role in the pathways of central metabolism. Post-translational lipoylation of the dihydrolipoyl acyltransferase component of these complexes is essential for their activity, the lipoyllysine moiety performing the transfer of substrates and intermediates between the different active sites within these multienzyme systems. We have previously shown that the thermophilic archaeon, Thermoplasma acidophilum, has a four-gene cluster encoding the components of such a complex, which, when recombinantly expressed in Escherichia coli, can be assembled into an active multienzyme in vitro. Crucially, the E. coli host carries out the required lipoylation of the archaeal dihydrolipoyl acyltransferase component. Because active 2-oxoacid dehydrogenase multienzyme complexes have never been detected in any archaeon, the question arises as to whether Archaea possess a functional lipoylation system. In this study, we report the cloning and heterologous expression of two genes from Tp. acidophilum whose protein products together show significant sequence identity with the single lipoate protein ligase enzyme of bacteria. We demonstrate that both recombinantly expressed Tp. acidophilum proteins are required for lipoylation of the acyltransferase, and that the two proteins associate together to carry out this post-translational modification. From the published DNA sequences, we suggest the presence of functional transcriptional and translational regulatory elements, and furthermore we present preliminary evidence that lipoylation occurs in vivo in Tp. acidophilum. This is the first report of the lipoylation machinery in the Archaea, which is unique in that the catalytic activity is dependent on two separate gene products.
Original languageEnglish
Pages (from-to)4012-4022
Number of pages11
JournalFEBS Journal
Volume276
Issue number15
Early online date6 Jul 2009
DOIs
Publication statusPublished - Aug 2009

Keywords

  • synthase
  • 2-oxoacid dehydrogenase multienzyme complex
  • dehydrogenase multienzyme complex
  • Archaea
  • domains
  • ligase
  • lipoylation
  • post-translational modification
  • escherichia-coli
  • substrate
  • e3 components
  • lipoic acid
  • gene expression
  • thermophile

Fingerprint Dive into the research topics of 'A unique lipoylation system in the Archaea: lipoylation in <em>Thermoplasma acidophilum</em> requires two proteins'. Together they form a unique fingerprint.

Cite this