- Heme enzymes. Neutron cryo-crystallography captures the protonation state of ferryl heme in a peroxidase.
Heme enzymes. Neutron cryo-crystallography captures the protonation state of ferryl heme in a peroxidase.
Science (New York, N.Y.) (2014-07-12)
Cecilia M Casadei, Andrea Gumiero, Clive L Metcalfe, Emma J Murphy, Jaswir Basran, Maria Grazia Concilio, Susana C M Teixeira, Tobias E Schrader, Alistair J Fielding, Andreas Ostermann, Matthew P Blakeley, Emma L Raven, Peter C E Moody
PMID25013070
ABSTRACT
Heme enzymes activate oxygen through formation of transient iron-oxo (ferryl) intermediates of the heme iron. A long-standing question has been the nature of the iron-oxygen bond and, in particular, the protonation state. We present neutron structures of the ferric derivative of cytochrome c peroxidase and its ferryl intermediate; these allow direct visualization of protonation states. We demonstrate that the ferryl heme is an Fe(IV)=O species and is not protonated. Comparison of the structures shows that the distal histidine becomes protonated on formation of the ferryl intermediate, which has implications for the understanding of O-O bond cleavage in heme enzymes. The structures highlight the advantages of neutron cryo-crystallography in probing reaction mechanisms and visualizing protonation states in enzyme intermediates.
MATERIALS
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Brand
Product Description
Iron, insulated wire, 10m, conductor diameter 0.25mm, insulation thickness 0.01mm, polyester insulation
Iron, tube, 1000mm, outside diameter 12.0mm, inside diameter 9mm, wall thickness 1.5mm, annealed, 99.5%
Iron, tube, 1000mm, outside diameter 25.0mm, inside diameter 21mm, wall thickness 2mm, annealed, 99.5%
Iron, tube, 200mm, outside diameter 6.35mm, inside diameter 5.35mm, wall thickness 0.5mm, as drawn, 99.8%
Iron, tube, 500mm, outside diameter 12.7mm, inside diameter 9.5mm, wall thickness 1.6mm, annealed, 99.5%
Iron, tube, 200mm, outside diameter 2.38mm, inside diameter 1.6mm, wall thickness 0.39mm, as drawn, 99.8+%
Iron, tube, 100mm, outside diameter 3.18mm, inside diameter 1.96mm, wall thickness 0.61mm, as drawn, 99.5%
Iron, tube, 200mm, outside diameter 2.0mm, inside diameter 1.6mm, wall thickness 0.2mm, as drawn, 99.5%
Iron, tube, 200mm, outside diameter 10.0mm, inside diameter 7mm, wall thickness 1.5mm, annealed, 99.5%
Iron, tube, 200mm, outside diameter 20.0mm, inside diameter 16mm, wall thickness 2.0mm, annealed, 99.5%
Iron, tube, 500mm, outside diameter 15.0mm, inside diameter 12mm, wall thickness 1.5mm, annealed, 99.5%
Iron, tube, 500mm, outside diameter 3.18mm, inside diameter 1.96mm, wall thickness 0.61mm, as drawn, 99.5%
Iron, tube, 500mm, outside diameter 5.0mm, inside diameter 4.5mm, wall thickness 0.25mm, as drawn, 99.5%
Iron, tube, 200mm, outside diameter 10.6mm, inside diameter 10.0mm, wall thickness 0.3mm, as drawn, 99.8+%
Iron, tube, 100mm, outside diameter 12.7mm, inside diameter 9.5mm, wall thickness 1.6mm, annealed, 99.5%
Iron, tube, 1000mm, outside diameter 12.0mm, inside diameter 10mm, wall thickness 1.0mm, annealed, 99.5%
Iron, tube, 200mm, outside diameter 25.0mm, inside diameter 21mm, wall thickness 2mm, annealed, 99.5%
Iron, tube, 1000mm, outside diameter 8.0mm, inside diameter 5mm, wall thickness 1.5mm, annealed, 99.5%
Iron, tube, 1000mm, outside diameter 5.0mm, inside diameter 4.5mm, wall thickness 0.25mm, as drawn, 99.5%
Iron, tube, 100mm, outside diameter 10.0mm, inside diameter 7mm, wall thickness 1.5mm, annealed, 99.5%
Iron, tube, 500mm, outside diameter 1.0mm, inside diameter 0.8mm, wall thickness 0.1mm, as drawn, 99.5%
Iron, tube, 500mm, outside diameter 1.65mm, inside diameter 0.89mm, wall thickness 0.38mm, as drawn, 99.8+%
Iron, tube, 200mm, outside diameter 12.0mm, inside diameter 10mm, wall thickness 1.0mm, annealed, 99.5%
Iron, tube, 1000mm, outside diameter 3.2mm, inside diameter 2.2mm, wall thickness 0.5mm, as drawn, 99.8%
Iron, tube, 500mm, outside diameter 6.35mm, inside diameter 5.35mm, wall thickness 0.5mm, as drawn, 99.8%
Iron, tube, 200mm, outside diameter 3.18mm, inside diameter 1.96mm, wall thickness 0.61mm, as drawn, 99.5%
Supelco
L-Histidine, certified reference material, TraceCERT®, Manufactured by: Sigma-Aldrich Production GmbH, Switzerland
Iron, IRMM®, certified reference material, 0.5 mm wire