Iron superoxide dismutase from the archaeon Sulfolobus solfataricus: Average hydrophobicity and amino acid weight are involved in the adaptation of proteins to extreme environments

Antonio Dello Russo, Rosario Rullo, Gianpaolo Nitti, Mariorosario Masullo, Vincenzo Bocchini

Research output: Contribution to journalArticle


The iron-superoxide dismutase in the thermoacidophilic archaeon Sulfolobus solfataricus has a homodimeric structure with a metal content of 0.7 atom of iron per subunit. The enzyme is insensitive to cyanide inhibition, sensitive to inactivation by H2O2 and is the most heat resistant SOD known so far being its half-life 2 h at 100°C. Its primary structure was determined by a profitable combination of advanced mass spectrometry and automated sequence analysis of peptides obtained after cleavage of the purified protein. The enzyme subunit is composed of 210 amino acid residues accounting for a relative molecular mass of 24 112. It does not contain cysteine residues and has a high average of both hydrophobicity and amino acid weight. Vice versa, the hydrophobicity is lower in halophilic SODs. Therefore, it seems that the average hydrophobicity is involved in the adaptation of proteins to extreme environments. The multiple alignment of the primary structure of archaeal and thermophilic eubacterial SODs indicated that archaeal SODs evolved separately from the thermophilic eubacterial SODs and that halophiles originated from a gene different from that of thermophilic archaea.

Original languageEnglish
Pages (from-to)23-30
Number of pages8
JournalBiochimica et Biophysica Acta (BBA)/Protein Structure and Molecular
Issue number1
Publication statusPublished - Nov 14 1997



  • (Sulfolobus solfataricus)
  • Hydrophobicity
  • Primary structure
  • SOD
  • Thermostability

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Structural Biology
  • Biophysics

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