Cryo-trapping the six-coordinate, distorted-octahedral active site of manganese superoxide dismutase

Gloria E Borgstahl, Matthew Pokross, Ramsey Chehab, Anuradha Sekher, Edward H. Snell

Research output: Contribution to journalArticle

69 Citations (Scopus)

Abstract

Superoxide dismutase protects organisms from potentially damaging oxygen radicals by catalyzing the disproportionation of superoxide to oxygen and hydrogen peroxide. We report the use of cryogenic temperatures to kinetically capture the sixth ligand bound to the active site of manganese superoxide dismutase (MnSOD). Synchrotron X-ray diffraction data was collected from Escherichia coli MnSOD crystals grown at pH 8.5 and cryocooled to 100 K. Structural refinement to 1.55 Å resolution and close inspection of the active site revealed electron density for a sixth ligand that was interpreted to be a hydroxide ligand. The six-coordinate, distorted-octahedral geometry assumed during inhibition by hydroxide is compared to the room temperature, five-coordinate, trigonal bipyramidal active site determined with crystals grown from practically identical conditions. The gateway residues Tyr34, His30 and a tightly bound water molecule are implicated in closing-off the active site and blocking the escape route of the sixth ligand. (C) 2000 Academic Press.

Original languageEnglish (US)
Pages (from-to)951-959
Number of pages9
JournalJournal of Molecular Biology
Volume296
Issue number4
DOIs
StatePublished - Mar 3 2000

Fingerprint

Superoxide Dismutase
Catalytic Domain
Ligands
Synchrotrons
Temperature
X-Ray Diffraction
Superoxides
Hydrogen Peroxide
Reactive Oxygen Species
Electrons
Oxygen
Escherichia coli
Water
hydroxide ion

Keywords

  • Cryocrystallography
  • Manganese
  • Metalloprotein
  • Solvent structure
  • Superoxide dismutase

ASJC Scopus subject areas

  • Molecular Biology

Cite this

Cryo-trapping the six-coordinate, distorted-octahedral active site of manganese superoxide dismutase. / Borgstahl, Gloria E; Pokross, Matthew; Chehab, Ramsey; Sekher, Anuradha; Snell, Edward H.

In: Journal of Molecular Biology, Vol. 296, No. 4, 03.03.2000, p. 951-959.

Research output: Contribution to journalArticle

Borgstahl, Gloria E ; Pokross, Matthew ; Chehab, Ramsey ; Sekher, Anuradha ; Snell, Edward H. / Cryo-trapping the six-coordinate, distorted-octahedral active site of manganese superoxide dismutase. In: Journal of Molecular Biology. 2000 ; Vol. 296, No. 4. pp. 951-959.
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AU - Snell, Edward H.

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