Dissertation
Characterization and Redox Interaction of Cytochrome P450 and Cytochrome P450 Reductase From Sorghum Bicolor
Washington State University
Doctor of Philosophy (PhD), Washington State University
2022
DOI:
https://doi.org/10.7273/000005183
Abstract
Bioenergy sorghums (Sorghum bicolor (L.) Moench) are cultivated to produce large volumes of biomass. In the context of bioenergy production, lignin has been the focus of much attention because of the negative role it plays in the enzymatic saccharification of cell wall polysaccharides. Lignin is formed from the oxidative coupling of monolignols, which are hydroxycinnamyl alcohols and related compounds synthesized from 4-coumaroyl-CoA via a series of enzymatic reactions. The detailed mechanism of the monolignol pathway will enable the manipulation of lignin content in biofuel plants, and further benefits biofuel production. Much progress has been made in the understanding of lignin biosynthesis through detailed studies of the enzymes involved in the biosynthesis of monolignols, while the crucial hydroxylation steps are poorly understood. The hydroxylation steps in the monolignol pathway are achieved by cytochrome P450s, including p-coumaroyl shikimate 3'-hydroxylase (C3’H), cinnamate-4-hydroxylase (C4H), and ferulate-5-hydroxylase (F5H). These three enzymes belong to the class II P450 superfamily, where the electrons necessary for catalysis are provided by NADPH-dependent cytochrome P450 reductase (CPR), a flavoprotein co-localized with P450 on the exterior surface of the membrane of endoplasmic reticulum (ER). This study investigated the structural and functional characteristics of p-coumaroyl shikimate 3'-hydroxylase (C3’H), cinnamate-4-hydroxylase (C4H), cytochrome P450 reductases from sorghum, as well as the redox interaction between the P450s and CPRs. The results provide valuable information of the substrate specificity and protein-protein interaction of the key enzymes in the monolignol pathway, thus contribute to the fundamental knowledge to tune the chemical composition in the secondary cell walls of plants.
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Details
- Title
- Characterization and Redox Interaction of Cytochrome P450 and Cytochrome P450 Reductase From Sorghum Bicolor
- Creators
- Bixia Zhang
- Contributors
- ChulHee Kang (Advisor)Clifford E Berkman (Committee Member)James A Brozik (Committee Member)Dmitri R Davydov (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Chemistry, Department of
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 206
- Identifiers
- 99901019940601842
- Language
- English
- Resource Type
- Dissertation