Subjects: Biology >> Biophysics submitted time 2016-05-12
Chen, Xuemin
Pu, Hua
Fang, Ying
Wang, Xiao
Zhao, Shun
Dai, Huai-En
Liu, Lin
Chen, Xuemin
Pu, Hua
Fang, Ying
Wang, Xiao
Zhao, Shun
Lin, Yajing
Gong, Weimin
Zhang, Min
Gong, Weimin
Abstract： Tetrapyrroles, including haem and chlorophyll, play vital roles for various biological processes, such as respiration and photosynthesis, and their biosynthesis is critical for virtually all organisms. In photosynthetic organisms, magnesium chelatase (MgCh) catalyses insertion of magnesium into the centre of protoporphyrin IX, the branch-point precursor for both haem and chlorophyll, leading tetrapyrrole biosynthesis into the magnesium branch1,2. This reaction needs a cooperated action of the three subunits of MgCh: the catalytic subunit ChlH and two AAA(+) subunits, ChlI and ChlD ( refs 3-5). To date, the mechanism of MgCh awaits further elucidation due to a lack of high-resolution structures, especially for the similar to 150 kDa catalytic subunit. Here we report the crystal structure of ChlH from the photosynthetic cyanobacterium Synechocystis PCC 6803, solved at 2.5 angstrom resolution. The active site is buried deeply inside the protein interior, and the surrounding residues are conserved throughout evolution. This structure helps to explain the loss of function reported for the cch and gun5 mutations of the ChlH subunit, and to provide the molecular basis of substrate channelling during the magnesium-chelating process. The structure advances our understanding of the holoenzyme of MgCh, a metal chelating enzyme other than ferrochelatase.
Peer Review Status:
Awaiting Review
Subjects: Biology >> Biophysics submitted time 2016-05-05
Wang, Xianlong
Cao, Chunwei
Huang, Jiaojiao
Yao, Jing
Hai, Tang
Zheng, Qiantao
Wang, Xiao
Zhang, Hongyong
Qin, Guosong
Zhou, Qi
Wang, Hongmei
Zhao, Jianguo
Zheng, Qiantao
Wang, Xiao
Zhang, Hongyong
Zhou, Qi
Wang, Hongmei
Zhao, Jianguo
Cheng, Jinbo
Yuan, Zengqiang
Abstract： Pig shows multiple superior characteristics in anatomy, physiology, and genome that have made this species to be more suitable models for human diseases, especially for neurodegenerative diseases, because they have similar cerebral convolutions compared with human neocortex. Recently, CRISPR/Cas9 system shows enormous potential for engineering the pig genome. In this study, we expect to generate human Parkinson's disease pig model using CRISPR/Cas9 system by simultaneously targeting three distinct genomic loci, parkin/DJ-1/PINK1, in Bama miniature pigs. By co-injection of Cas9 mRNA and multiplexing single guide RNAs (sgRNAs) targeting parkin, DJ-1, and PINK1 genes, respectively, into in vivo derived pronuclear embryos, we simultaneously targeted three distinct genomic loci. The gene modified piglets remain healthy and display normal behavior at the age of 10 months. In addition, despite the high number of sgRNAs were employed in the present study, our trio-based whole-genome sequencing analysis suggested that the incidence of off-target events is low. Our results demonstrate that the simplicity, efficiency, and power of the CRISPR/Cas9 system to allow for the modification of multiple genes in pigs and yield results of high medical value.
Peer Review Status:Awaiting Review
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