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Title
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Crystallographic determination of the active site iron and its ligands in soybean lipoxygenase L-1.
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Authors
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W.Minor,
J.Steczko,
J.T.Bolin,
Z.Otwinowski,
B.Axelrod.
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Ref.
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Biochemistry, 1993,
32,
6320-6323.
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PubMed id
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Abstract
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Five ligands of the active site iron atom in soybean lipoxygenase L-1 have been
identified from the electron density map of the crystallized enzyme. The
position of the iron atom can be readily and independently located from an
anomalous difference electron density map. The ligands identified are His-499,
His-504, His-690, Asn-694, and Ile-839, the carboxy-terminal residue. Our
previous view that these three histidines are essential for activity and binding
of iron, based on site-specific mutation studies, is confirmed. A sixth protein
ligand is not present, and the sixth coordination site opens into a wide cleft.
The structure of the soybean lipoxygenase was solved by multiple anomalous
isomorphous replacements.
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