Structural highlights
1fgm is a 1 chain structure with sequence from Glycine hispida. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
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| Ligands: | |
| Related: | 1yge, 1f8n, 1fgo, 1fgq, 1fgr, 1fgt |
| Activity: | Oxidoreductase, with EC number 1.13.11.12 |
| Resources: | FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT |
Function
[LOX1_SOYBN] Plant lipoxygenase may be involved in a number of diverse aspects of plant physiology including growth and development, pest resistance, and senescence or responses to wounding. With linoleate as substrate, L-1 shows a preference for carbon 13 as the site for hydroperoxidation (in contrast to L-2 and L-3, which utilize either carbon 9 or 13). At pH above 8.5, only (9Z,11E,13S)-13-hydroperoxyoctadeca-9,11-dienoate is produced, but as the pH decreases, the proportion of (9S)-hydroperoxide increases linearly until at pH 6.0 it represents about 25 % of the products.[1]
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
Lipoxygenases are an important class of non-heme iron enzymes that catalyze the hydroperoxidation of unsaturated fatty acids. The details of the enzymatic mechanism of lipoxygenases are still not well understood. This study utilizes a combination of kinetic and structural probes to relate the lipoxygenase mechanism of action with structural modifications of the iron's second coordination sphere. The second coordination sphere consists of Gln(495) and Gln(697), which form a hydrogen bond network between the substrate cavity and the first coordination sphere (Asn(694)). In this investigation, we compared the kinetic and structural properties of four mutants (Q495E, Q495A, Q697N, and Q697E) with those of wild-type soybean lipoxygenase-1 and determined that changes in the second coordination sphere affected the enzymatic activity by hydrogen bond rearrangement and substrate positioning through interaction with Gln(495). The nature of the C-H bond cleavage event remained unchanged, which demonstrates that the mutations have not affected the mechanism of hydrogen atom tunneling. The unusual and dramatic inverse solvent isotope effect (SIE) observed for the Q697E mutant indicated that an Fe(III)-OH(-) is the active site base. A new transition state model for hydrogen atom abstraction is proposed.
Structural and functional characterization of second-coordination sphere mutants of soybean lipoxygenase-1.,Tomchick DR, Phan P, Cymborowski M, Minor W, Holman TR Biochemistry. 2001 Jun 26;40(25):7509-17. PMID:11412104[2]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Coffa G, Imber AN, Maguire BC, Laxmikanthan G, Schneider C, Gaffney BJ, Brash AR. On the relationships of substrate orientation, hydrogen abstraction, and product stereochemistry in single and double dioxygenations by soybean lipoxygenase-1 and its Ala542Gly mutant. J Biol Chem. 2005 Nov 18;280(46):38756-66. Epub 2005 Sep 12. PMID:16157595 doi:http://dx.doi.org/10.1074/jbc.M504870200
- ↑ Tomchick DR, Phan P, Cymborowski M, Minor W, Holman TR. Structural and functional characterization of second-coordination sphere mutants of soybean lipoxygenase-1. Biochemistry. 2001 Jun 26;40(25):7509-17. PMID:11412104
