Structural conservation of the isolated zinc site in archaeal zinc- containing ferredoxins as revealed by x-ray absorption spectroscopic analysis and its evolutionary implications

Nathaniel J. Cosper, Christina M.V. Stålhandske, Hideo Iwasaki, Tairo Oshima, Robert A. Scott, Toshio Iwasaki

Research output: Contribution to journalArticle

10 Citations (Scopus)


The zfx gene encoding a zinc-containing ferredoxin from Thermoplasma acidophilum strain HO-62 was cloned and sequenced. It is located upstream of two genes encoding an archaeal homolog of nascent polypeptide-associated complex α subunit and a tRNA nucleotidyltransferase. This gene organization is not conserved in several euryarchaeoteal genomes. The multiple sequence alignments of the zfx gene product suggest significant sequence similarity of the ferredoxin core fold to that of a low potential 8Fe-containing dicluster ferredoxin without a zinc center. The tightly bound zinc site of zinc- containing ferredoxins from two phylogenetically distantly related Archaea, T. acidophilum HO-62 and Sulfolobus sp. strain 7, was further investigated by x-ray absorption spectroscopy. The zinc K-edge x-ray absorption spectra of both archaeal ferredoxins are strikingly similar, demonstrating that the same zinc site is found in T. acidophilum ferredoxin as in Sulfolobus sp. ferredoxin, which suggests the structural conservation of isolated zinc binding sites among archaeal zinc-containing ferredoxins. The sequence and spectroscopic data provide the common structural features of the archaeal zinc-containing ferredoxin family.

Original languageEnglish
Pages (from-to)23160-23168
Number of pages9
JournalJournal of Biological Chemistry
Issue number33
Publication statusPublished - 1999 Aug 13


ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Cite this