3bne
Lipoxygenase-1 (Soybean) I553A Mutant
Structural highlights
FunctionLOX1_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 PubMedThis study examines the impact of a series of mutations at position 553 on the kinetic and structural properties of soybean lipoxygenase-1 (SLO-1). The previously uncharacterized mutants reported herein are I553L, I553V, and I553G. High-resolution x-ray studies of these mutants, together with the earlier studied I553A, show almost no structural change in relation to the WT-enzyme. By contrast, a progression in kinetic behavior occurs in which the decrease in the size of the side chain at position 553 leads to an increased importance of donor-acceptor distance sampling in the course of the hydrogen transfer process. These dynamical changes in behavior are interpreted in the context of two general classes of protein motions, preorganization and reorganization, with the latter including the distance sampling modes [Klinman JP (2006) Philos Trans R Soc London Ser B 361:1323-1331; Nagel Z, Klinman JP (2006) Chem Rev 106:3095-3118]. The aggregate data for SLO-1 show how judicious placement of hydrophobic side chains can influence enzyme catalysis via enhanced donor-acceptor hydrogenic wave function overlap. Enzyme structure and dynamics affect hydrogen tunneling: the impact of a remote side chain (I553) in soybean lipoxygenase-1.,Meyer MP, Tomchick DR, Klinman JP Proc Natl Acad Sci U S A. 2008 Jan 29;105(4):1146-51. Epub 2008 Jan 23. PMID:18216254[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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