Carotenoid biosynthesis and overproduction in Corynebacterium glutamicum.
Carotenoid biosynthesis and overproduction in Corynebacterium glutamicum.
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DOI：
10.1186/1471-2180-12-198
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发表时间：
2012-09-10
期刊：
影响因子：
4.2
通讯作者：
Wendisch VF
中科院分区：
文献类型：
--
作者：
Heider SA;Peters-Wendisch P;Wendisch VF
谷氨酸棒杆菌含有糖基化的C50类胡萝卜素十肾上腺黄素作为黄色色素。从异戊烯焦磷酸（其在非甲羟戊酸途径中产生）开始，经由中间体法呢基焦磷酸、香叶基香叶基焦磷酸、番茄红素和黄嘌呤合成十肾上腺黄素。在这里，我们表明，类胡萝卜素基因簇crtE-cg 0722-crtBIYeYfEb的基因是共转录的，其特征在于定义的基因缺失突变体。基因缺失分析显示crtI、crtEb和crtYeYf分别编码仅有的八氢番茄红素去饱和酶、番茄红素延伸酶和类胡萝卜素C45/C50 β-环化酶。然而，C.谷氨酸还编码第二个类胡萝卜素基因簇，该基因簇包含crtB 2 I2 -1/2，该基因簇也被共转录。crtB 2的异位表达可以弥补八氢番茄红素合成酶CrtB在C. glutamicum ΔcrtB，因此C.谷氨酸单胞菌具有两种功能性八氢番茄红素脱氢酶，即CrtB和CrtB 2。不能获得crtI 2 -1/2编码八氢番茄红素去饱和酶的遗传证据，因为crtI 2 -1/2的质粒携带表达不能补偿C.谷氨酸ΔcrtI. C.以番茄红素为例，研究了谷氨酸对类胡萝卜素过量产生的影响。基因crtEb的缺失阻止番茄红素转化为十肾上腺黄素，并导致番茄红素积累至0.03 ± 0.01 mg/g细胞干重（CDW）。当将牛儿基牛儿基焦磷酸转化为番茄红素的基因crtE、crtB和crtI在C.结果表明，在培养条件下，谷氨酸ΔcrtEb细胞呈强烈的红色，番茄红素含量增加了80倍，为2.4 ± 0.3mg/gCDW。C.由于谷氨酸菌具有两个功能性八氢番茄红素合酶基因，因此其在C50类胡萝卜素十肾上腺黄素的生物合成中具有一定程度的冗余。仅对产生番茄红素的末端反应进行代谢工程已经导致了相当多的番茄红素生产，这表明C。谷氨酸菌可作为类胡萝卜素生产的潜在宿主。
Corynebacterium glutamicum contains the glycosylated C50 carotenoid decaprenoxanthin as yellow pigment. Starting from isopentenyl pyrophosphate, which is generated in the non-mevalonate pathway, decaprenoxanthin is synthesized via the intermediates farnesyl pyrophosphate, geranylgeranyl pyrophosphate, lycopene and flavuxanthin. Here, we showed that the genes of the carotenoid gene cluster crtE-cg0722-crtBIYeYfEb are co-transcribed and characterized defined gene deletion mutants. Gene deletion analysis revealed that crtI, crtEb, and crtYeYf, respectively, code for the only phytoene desaturase, lycopene elongase, and carotenoid C45/C50 ɛ-cyclase, respectively. However, the genome of C. glutamicum also encodes a second carotenoid gene cluster comprising crtB2I2-1/2 shown to be co-transcribed, as well. Ectopic expression of crtB2 could compensate for the lack of phytoene synthase CrtB in C. glutamicum ΔcrtB, thus, C. glutamicum possesses two functional phytoene synthases, namely CrtB and CrtB2. Genetic evidence for a crtI2-1/2 encoded phytoene desaturase could not be obtained since plasmid-borne expression of crtI2-1/2 did not compensate for the lack of phytoene desaturase CrtI in C. glutamicum ΔcrtI. The potential of C. glutamicum to overproduce carotenoids was estimated with lycopene as example. Deletion of the gene crtEb prevented conversion of lycopene to decaprenoxanthin and entailed accumulation of lycopene to 0.03 ± 0.01 mg/g cell dry weight (CDW). When the genes crtE, crtB and crtI for conversion of geranylgeranyl pyrophosphate to lycopene were overexpressed in C. glutamicum ΔcrtEb intensely red-pigmented cells and an 80 fold increased lycopene content of 2.4 ± 0.3 mg/g CDW were obtained. C. glutamicum possesses a certain degree of redundancy in the biosynthesis of the C50 carotenoid decaprenoxanthin as it possesses two functional phytoene synthase genes. Already metabolic engineering of only the terminal reactions leading to lycopene resulted in considerable lycopene production indicating that C. glutamicum may serve as a potential host for carotenoid production.
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影响因子：
11.4
作者：
Choudhari, Sheetal M.;Ananthanarayan, Laxmi;Singhal, Rekha S.
通讯作者：
Singhal, Rekha S.
影响因子：
4.1
作者：
Kohl, Thomas A.;Tauch, Andreas
通讯作者：
Tauch, Andreas
影响因子：
3.2
作者：
Netzer, Roman;Stafsnes, Marit H.;Brautaset, Trygve
通讯作者：
Brautaset, Trygve
影响因子：
1.2
作者：
ABE, S;TAKAYAMA, KI;KINOSHITA, S
通讯作者：
KINOSHITA, S
影响因子：
2.8
作者：
Krubasik, P;Takaichi, S;Sandmann, G
通讯作者：
Sandmann, G