Lipoxygenases, which are widely distributed among plant and animal species, are Fe-containing dioxygenases that act on lipids containing (Z,Z)-pentadiene moieties in the synthesis of compounds with a variety of functions. Utilizing an improved strategy of data collection, low temperature, and synchrotron radiation of short wavelength, the structure of ferrous soybean lipoxygenase L-1, a single chain protein of 839 amino acid residues, has been determined by X-ray crystallography to a resolution of 1 ...
Lipoxygenases, which are widely distributed among plant and animal species, are Fe-containing dioxygenases that act on lipids containing (Z,Z)-pentadiene moieties in the synthesis of compounds with a variety of functions. Utilizing an improved strategy of data collection, low temperature, and synchrotron radiation of short wavelength, the structure of ferrous soybean lipoxygenase L-1, a single chain protein of 839 amino acid residues, has been determined by X-ray crystallography to a resolution of 1.4 A. The R-factor for the refined model is 19.7%. General features of the protein structure were found to be consistent with the results of prior crystallographic studies at lower (2.6 A) resolution. In contrast to the prior studies, the binding of a water molecule to the active site Fe was established. The octahedral coordination sphere of the Fe also includes the side chains of His499, His504, His690, and Asn694 as well as the terminal carboxylate of Ile839, which binds as a monodentate ligand. Asn694 is involved in a number of labile polar interactions with other protein groups, including an amide-aromatic hydrogen bond, and appears to be a weak ligand. Several possible access routes for dioxygen and fatty acids to the internal active site and substrate binding cavity are described. The protein structure restricts access to the Fe site such that the formation of an organo-Fe intermediate seems improbable. Structural restrictions pertinent to other proposed reaction intermediates, such as planar pentadienyl and nonplanar allyl radicals, are also discussed.
Related Citations:
Position 713 is Critical for Catalysis But not Iron Binding in Soybean Lipoxygenase Kramer, J.A., Johnson, K.R., Dunham, W.R., Sands, R.H., Funk Junior, M.O. (1994) Biochemistry 33: 15017
The Structure and Function of Lipoxygenase Nelson, M.J., Seitz, S.P. (1994) Curr Opin Struct Biol 4: 878
Structural Characterization of Alkyl and Peroxyl Radicals in Solutions of Purple Lipoxygenase Nelson, M.J., Cowling, R.A., Seitz, S.P. (1994) Biochemistry 33: 4966
X-Ray Spectroscopy of the Iron Site in Soybean Lipoxygenase-1: Changes in Coordination Upon Oxidation or Addition of Methanol Scarrow, R.C., Trimitsis, M.G., Buck, C.P., Grove, G.N., Cowling, R.A., Nelson, M.J. (1994) Biochemistry 33: 15023
The Three-Dimensional Structure of an Arachidonic Acid 15-Lipoxygenase Boyington, J.C., Gaffney, B.J., Amzel, L.M. (1993) Science 260: 1482
Crystallographic Determination of the Active Site Iron and its Ligands in Soybean Lipoxygenase L-1 Minor, W., Steczko, J., Bolin, J.T., Otwinowski, Z., Axelrod, B. (1993) Biochemistry 32: 6320
Conserved Histidine Residues in Soybean Lipoxygenase: Functional Consequences of Their Replacement Steczko, J., Donoho, G.P., Clemens, J.C., Dixon, J.E., Axelrod, B. (1992) Biochemistry 31: 4053
Spectroscopic Studies of the Non-Heme Ferric Active Site in Soybean Lipoxygenase: Magnetic Circular Dichroism as a Probe of Electronic and Geometric Structure. Ligand-Field Origin of Zero-Field Zhang, Y., Gebhard, M.S., Solomon, E.I. (1991) J Am Chem Soc 113: 5162
Crystallization and Preliminary X-Ray Investigation of Lipoxygenase 1 from Soybeans Steczko, J., Muchmore, C.R., Smith, J.L., Axelrod, B. (1990) J Biol Chem 265: 11352
Organizational Affiliation:
Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907, USA.
Download Mendeley
