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PDBsum entry 1lnh
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Oxidoreductase
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PDB id
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1lnh
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References listed in PDB file
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Key reference
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Title
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Structure of soybean lipoxygenase l3 and a comparison with its l1 isoenzyme.
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Authors
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E.Skrzypczak-Jankun,
L.M.Amzel,
B.A.Kroa,
M.O.Funk.
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Ref.
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Proteins, 1997,
29,
15-31.
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PubMed id
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Abstract
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Soybean lipoxygenase isoenzyme L3 represents a second example (after L1) of the
X-ray structure (R = 17% at 2.6 A resolution) for a member of the large family
of lipoxygenases. L1 and L3 have different characteristics in catalysis,
although they share 72% sequence identity (the changes impact 255 amino acids)
and similar folding (average C alpha rms deviation of 1 A). The critical nonheme
iron site has the same features as for L1:3O and 3N in pseudo C3v orientation,
with two oxygen atoms (from Asn713 and water) at a nonbinding distance. Asn713
and His518 are strategically located at the junction of three cavities
connecting the iron site with the molecule surface. The most visible differences
between L1 and L3 isoenzymes occur in and near these cavities, affecting their
accessibility and volume. Among the L1/L3 substitutions Glu256/ Thr274,
Tyr409/His429, and Ser747/Asp766 affect the salt bridges (L1: Glu256...His248
and Asp490...Arg707) that in L1 restrict the access to the iron site from two
opposite directions. The L3 molecule has a passage going through the whole
length of the helical domain, starting at the interface with the Nt-domain (near
25-27 and 254-278) and going to the opposite end of the Ct-domain (near 367,
749). The substrate binding and the role of His513, His266, His776 (and other
residues nearby) are illustrated and discussed by using models of linoleic acid
binding. These hypotheses provide a possible explanation for a stringent
stereo-specificity of catalytic products in L1 (that produces predominantly
13-hydroperoxide) versus the lack of such specificity in L3 (that turns out a
mixture of 9- and 13-hydroperoxides and their diastereoisomers).
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Secondary reference #1
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Title
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Lipoxygenase - A molecular complex with a non-Heme iron
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Authors
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E.Skrzypczak-Jankun,
M.O.Funk junior,
J.C.Boyington,
L.M.Amzel.
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Ref.
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j mol struct, 1996,
374,
47.
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Secondary reference #2
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Title
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Position 713 is critical for catalysis but not iron binding in soybean lipoxygenase 3.
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Authors
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J.A.Kramer,
K.R.Johnson,
W.R.Dunham,
R.H.Sands,
M.O.Funk.
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Ref.
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Biochemistry, 1994,
33,
15017-15022.
[DOI no: ]
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PubMed id
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Secondary reference #3
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Title
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Crystallization and preliminary X-Ray characterization of a soybean seed lipoxygenase.
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Authors
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W.C.Stallings,
B.A.Kroa,
R.T.Carroll,
A.L.Metzger,
M.O.Funk.
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Ref.
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J Mol Biol, 1990,
211,
685-687.
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PubMed id
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