The molecular steps of citrinin biosynthesis in fungi.
The molecular steps of citrinin biosynthesis in fungi.
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DOI：
10.1039/c5sc04027b
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发表时间：
2016-03-01
期刊：
影响因子：
8.4
通讯作者：
Cox RJ
中科院分区：
文献类型：
--
作者：
He Y;Cox RJ
桔霉素聚酮合酶，CitS，加上剪裁酶CitA-CitE的异源表达，首次充分阐明了桔霉素的生物合成途径，显示了真菌中的托酚酮，azaphilone和sorbicillinoid生物合成途径的关系。通过靶向基因敲除和异源基因在曲霉中的表达相结合，确定了红曲霉M7中桔霉素1生物合成的各个步骤。该途径涉及通过称为CitS的非还原性聚酮化合物合酶（nrPKS）合成未还原的三甲基化喷他凯肽10。还原释放产生酮醛2作为第一个无酶中间体。nrPKS似乎得到了CitA催化的迄今为止神秘的水解步骤的帮助，CitA之前被错误地注释为氧化酶。CitB是一种非血红素铁氧化酶，可将2的12-甲基氧化为醇。随后的步骤由CitC和CitD催化，CitC将12-醇氧化为醛，CitD将12-醛转化为羧酸。C-3通过CitE的最终还原产生桔霉素。该途径排除了涉及分子内重排的替代方案，并首次完全定义了分子步骤，并纠正了文献中以前的错误。CitB的活性将该途径与真菌托酚酮生物合成联系起来，并且胺化分流产物的观察将该途径与azaphilone生物合成联系起来。通过在异源宿主A中协调生产CitS + CitA-CitE来生产桔霉素。其中每个基因由组成型启动子驱动，以高产率实现。
Heterologous expression of the citrinin polyketide synthase, CitS, plus the tailoring enzymes CitA–CitE from Monascus ruber has fully elucidated the biosynthetic pathway to citrinin for the first time, showing relationships to tropolone, azaphilone and sorbicillinoid biosynthetic pathways in fungi. The individual steps of citrinin 1 biosynthesis in Monascus ruber M7 were determined by a combination of targeted gene knockout and heterologous gene expression in Aspergillus oryzae. The pathway involves the synthesis of an unreduced trimethylated pentaketide 10 by a non-reducing polyketide synthase (nrPKS) known as CitS. Reductive release yields the keto-aldehyde 2 as the first enzyme-free intermediate. The nrPKS appears to be assisted by an as-yet cryptic hydrolysis step catalysed by CitA which was previously wrongly annotated as an oxidase. CitB is a non-heme iron oxidase which oxidises the 12-methyl of 2 to an alcohol. Subsequent steps are catalysed by CitC which oxidises the 12-alcohol to an aldehyde and CitD which converts the 12-aldehyde to a carboxylic acid. Final reduction of C-3 by CitE yields citrinin. The pathway rules out alternatives involving intramolecular rearrangements, and fully defines the molecular steps for the first time and corrects previous errors in the literature. The activity of CitB links the pathway to fungal tropolone biosynthesis and the observation of aminated shunt products links the pathway to azaphilone biosynthesis. Production of citrinin by coordinated production of CitS + CitA–CitE in the heterologous host A. oryzae, in which each gene was driven by a constitutive promoter, was achieved in high yield.
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DOI：
10.1039/c39800001132
发表时间：
1980-01-01
影响因子：
--
作者：
COLOMBO, L;GENNARI, C;MERENDI, C
通讯作者：
MERENDI, C
影响因子：
15
作者：
KANCHUGER, MS;BYERS, LD
通讯作者：
BYERS, LD
DOI：
10.1098/rstb.1931.0025
发表时间：
1931-05-01
影响因子：
--
作者：
Hetherington, AC;Raistrick, H
通讯作者：
Raistrick, H
影响因子：
4.9
作者：
Bailey, Andrew M.;Cox, Russell J.;Skellam, Elizabeth
通讯作者：
Skellam, Elizabeth
影响因子：
3.3
作者：
CHAGAS, GM;CAMPELLO, AP;KLUPPEL, LW
通讯作者：
KLUPPEL, LW