engineered reversal of the β -oxidation cycle for the synthesis of fuels and chemicals
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Engineered reversal of the β -oxidation cycle for the synthesis of fuels and chemicals. 报告人:张文倩 时间: 2011.10.07. Functional reversal of the β -oxidation cycle. 前期准备:对 β -oxidation 的正调控. RB01: MG1655. fadR atoC(c) crp* Δ arcA. 脂肪酸底物不存在的情况下反应仍能进行. 去除 arcA 介导 - PowerPoint PPT PresentationTRANSCRIPT
Engineered reversal Engineered reversal of the of the
ββ-oxidation cycle for -oxidation cycle for thethe
synthesis of fuels synthesis of fuels and chemicalsand chemicals报告人:张文倩
时间: 2011.10.07
Functional reversal of the β-oxidation Functional reversal of the β-oxidation cyclecycle
前期准备:对前期准备:对 ββ-oxidation-oxidation 的正调的正调控控
RB01: MG1655RB01: MG1655
fadR atoC(c) crp* ΔΔarcA
使之独立于cAMP
去除 arcAarcA 介导对 ββ-- 氧化的抑制作用
RB02: MG1655
fadR atoC(c) crp* ΔarcAfadR atoC(c) crp* ΔarcA
ΔΔadhEΔΔptaΔΔfrdA: 封锁其他代谢途径
脂肪酸底物不存在的情况下反应仍能进行
产乙酸产乙醇 产琥珀酸
针对一轮反应,以针对一轮反应,以 n-butanoln-butanol的合成为目标,的合成为目标,调节各步反应的基因调节各步反应的基因
终止反应:终止反应: YqhD FucOYqhD FucO 两个基因分别过表达 两个基因分别过表达
Butanol Butanol 产量升高产量升高
第一步 :第一步 : acetyl-CoA to acetoacetyl-CoAacetyl-CoA to acetoacetyl-CoA [atoB+] and [yqeF+] [atoB+] and [yqeF+] Butanol Butanol 产量升高产量升高
副产物副产物 ethanolethanol 的产量减少:的产量减少: ΔeutE ΔYqhDΔeutE ΔYqhD
总结各步反应总结各步反应
(( 11 ) ) YqeFYqeF
(( 22 ) ) FadBFadB
(( 33 ) ) FadBFadB(4 ) YdiO
(( 55 ) ) MhpF MhpF and and
FucOFucO
第四步:第四步: β-β- 氧化中唯一不可逆反应氧化中唯一不可逆反应 Ydio Ydio 替换 替换 FadEFadE
A new Escherichia coli metabolicA new Escherichia coli metaboliccompetency: growth on fatty acids competency: growth on fatty acids
by a novel anaerobic β-oxidation by a novel anaerobic β-oxidation pathway. Mol.Microbiol. 47, pathway. Mol.Microbiol. 47, 793793––805 (2003).805 (2003).
热力学可行性分析:: YdiQRST YdiQRST 编码 编码 ferredoxin and ferredoxin and
flavoproteinsflavoproteins ferredoxin ferredoxin 作 作 enoyl-CoA to acyl-CoA enoyl-CoA to acyl-CoA 的还的还
原力原力 ΔG 0﹤ΔG 0﹤
结论:结论: Ydio Ydio ––YdiQRSTYdiQRST 用于用于 enoyl-CoA to acyl-CoAenoyl-CoA to acyl-CoA 此步还原反应此步还原反应
逆反应
①
④
②
③
YqeFYqeF
FadBFadB
FadBFadB
YdiO FadEFadE
胞内中长链脂肪酸
奇偶数碳链醇
长链醇
短链脂肪酸
β-氧化逆反应
fatty-acid biosynthesis
keto-acid pathways
reversal of the β-oxidation cycle
66.7% C-mole basis
每加两个 C 原子单元,生成一个 ATP
直接以 acetyl-CoAacetyl-CoA 作碳原子供体作碳原子供体
acyl-CoA intermediatesacyl-CoA intermediates 作为作为 n-alcoholsn-alcohols 和其他产物的前体和其他产物的前体
Malonyl-ACP 的合成消耗 ATP
acyl-ACP intermediates 消耗ATP
a nonnatural metabolic engineering approach
目前合成最长碳链水平:己醇
50% C-mole
最后,与其他合成途径做对比
高效性