Crystal structure of linoleate 13R-manganese lipoxygenase in complex with an adhesion protein

Yang Chen,Anneli Wennman,Saeid Karkehabadi,Åke Engström,Ernst H Oliw

doi:10.1194/jlr.m069617

Yang Chen, Anneli Wennman + Show 3 more

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https://doi.org/10.1194/jlr.m069617

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Abstract

The crystal structure of 13R-manganese lipoxygenase (MnLOX) of Gaeumannomyces graminis (Gg) in complex with zonadhesin of Pichia pastoris was solved by molecular replacement. Zonadhesin contains β-strands in two subdomains. A comparison of Gg-MnLOX with the 9S-MnLOX of Magnaporthe oryzae (Mo) shows that the protein fold and the geometry of the metal ligands are conserved. The U-shaped active sites differ mainly due to hydrophobic residues of the substrate channel. The volumes and two hydrophobic side pockets near the catalytic base may sanction oxygenation at C-13 and C-9, respectively. Gly-332 of Gg-MnLOX is positioned in the substrate channel between the entrance and the metal center. Replacements with larger residues could restrict oxygen and substrate to reach the active site. C18 fatty acids are likely positioned with C-11 between Mn(2+)OH2 and Leu-336 for hydrogen abstraction and with one side of the 12Z double bond shielded by Phe-337 to prevent antarafacial oxygenation at C-13 and C-11. Phe-347 is positioned at the end of the substrate channel and replacement with smaller residues can position C18 fatty acids for oxygenation at C-9. Gg-MnLOX does not catalyze the sequential lipoxygenation of n-3 fatty acids in contrast to Mo-MnLOX, which illustrates the different configurations of their substrate channels.

Highlights

manganese lipoxygenase (MnLOX) of Magnaporthe oryzae (Mo) shows that the protein fold and the geometry of the metal ligands are conserved
Gaeumannomyces graminis (Gg)-MnLOX does not catalyze the sequential lipoxygenation of n-3 fatty acids in contrast to Mo-MnLOX, which illustrates the different configurations of their substrate channels.—Chen, Y., A
The third molecule, zonadhesin, consists of 587 residues (33), but the amino acids 1-19 and 340-587 could not be detected. Loss of the former as a secretion signal of 19 amino acids was confirmed by MALDI-TOF/TOF analysis of the tryptic peptide, which was formed by single cleavage, and contained residues 2032 as described above

Summary

Introduction

MnLOX of Magnaporthe oryzae (Mo) shows that the protein fold and the geometry of the metal ligands are conserved. The U-shaped active sites differ mainly due to hydrophobic residues of the substrate channel. The volumes and two hydrophobic side pockets near the catalytic base may sanction oxygenation at C-13 and C-9, respectively. MnLOX is positioned in the substrate channel between the entrance and the metal center. Replacements with larger residues could restrict oxygen and substrate to reach the acttiwveeesniteM. NC21+8OfHatt2y acids are likely positioned with C-11 beand Leu-336 for hydrogen abstraction and with one side of the 12Z double bond shielded by. Phe-347 is positioned at the end of the substrate channel and replacement with smaller residues can position C18 fatty acids for oxygenation at C-9. Gg-MnLOX does not catalyze the sequential lipoxygenation of n-3 fatty acids in contrast to Mo-MnLOX, which illustrates the different configurations of their substrate channels.—Chen, Y., A These oxylipins are formed during the pathogenic process and as defense molecules in the chemical warfare between plants, fungi, and bacteria (3)

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