Voltage-gated sodium （Nav） channels are essential for the rapid upstroke of action potentials and the propa- gation of electrical signals in nerves and muscles. Defects of Nav channels are associated with a variety ...Voltage-gated sodium （Nav） channels are essential for the rapid upstroke of action potentials and the propa- gation of electrical signals in nerves and muscles. Defects of Nav channels are associated with a variety of channelopathies. More than 1000 disease-related muta- tions have been identified in Nay channels, with Nay1.1 and Nay1.5 each harboring more than 400 mutations. Nay channels represent major targets for a wide array of neurotoxins and drugs. Atomic structures of Nav chan- nels are required to understand their function and dis- ease mechanisms. The recently determined atomic structure of the rabbit voltage-gated calcium （Car） channel Carl.1 provides a template for homology-based structural modeling of the evolutionarily related Nay channels. In this Resource article, we summarized all the reported disease-related mutations in human Nav channels, generated a homologous model of human Nay1.7, and structurally mapped disease-associated mutations. Before the determination of structures of human Nay channels, the analysis presented here serves as the base framework for mechanistic investi- gation of Nav channelopathies and for potential struc- ture-based drug discovery.展开更多
Transcription activator-like （TAL） effectors specifically bind to double stranded （ds） DNA through a central domain of tandem repeats. Each TAL effector （TALE） repeat comprises 33-35 amino acids and recognizes o...Transcription activator-like （TAL） effectors specifically bind to double stranded （ds） DNA through a central domain of tandem repeats. Each TAL effector （TALE） repeat comprises 33-35 amino acids and recognizes one specific DNA base through a highly variable residue at a fixed position in the repeat. Structural studies have revealed the molecular basis of DNA recognition by TALE repeats. Examination of the overall structure reveals that the basic building block of TALE protein, namely a helical hairpin, is one-helix shifted from the previously defined TALE motif. Here we wish to suggest a structure-based re-demarcation of the TALE repeat which starts with the residues that bind to the DNA backbone phosphate and concludes with the base-rec- ognition hyper-variable residue. This new numbering system is consistent with the （=-solenoid superfamily to which TALE belongs, and reflects the structural integrity of TAL effectors. In addition, it confers integral number of TALE repeats that matches the number of bound DNA bases. We then present fifteen crystal structures of engineered dHax3 variants in complex with target DNA molecules, which elucidate the structural basis for the recognition of bases adenine （A） and guanine （G） by reported or uncharacterized TALE codes. Finally, we analyzed the sequence-structure correlation of the amino acid residues within a TALE repeat. The structural analyses reported here may advance the mechanistic understanding of TALE proteins and facilitate the design of TALEN with improved affinity and specificity.展开更多
Manipulation of gene expression through targeting specific DNA or RNA sequences is a significant challenge, tn the past decade, transcription activator-like （TAL） effectors and zinc fingers （ZFs） have been success...Manipulation of gene expression through targeting specific DNA or RNA sequences is a significant challenge, tn the past decade, transcription activator-like （TAL） effectors and zinc fingers （ZFs） have been successfully developed into useful tools for DNA recognition （Bogdanove and Voytas, 2011; Deng et al., 2012a, 2012b）. However, little progress has been made in the realm of RNA targeting due to the lack of understanding about the modular RNA recognition mechanism.展开更多
Dear Editor,L-Fucose(6-deoxy-L-galactose,fucose)is the basic compone nt of a variety of glyca n structures.The fucosylated oligosaccharides participate in a variety of cellular activities,like the cell-cell recognitio...Dear Editor,L-Fucose(6-deoxy-L-galactose,fucose)is the basic compone nt of a variety of glyca n structures.The fucosylated oligosaccharides participate in a variety of cellular activities,like the cell-cell recognition,selectin-mediated leukocyteendothelial adhesion and the formation of Lewis blood group antigens(Ma et al.,2006).GDP-fucose is an important fucose donor in the process of fucosylated oligosaccharides formation.Two pathways of GDP-fucose synthesis are present in the cytosol of mammalian cells,including the de novo pathway and the salvage pathway(Becker et al.,2003).In the salvage pathway,cells use fucose from the extracellular or lysosomal sources to synthesize GDP-fucose.展开更多
Dear Editor, Voltage-gated sodium （Nav） channels are membrane pro- teins that are responsible for the propagation of action potentials in mammals by mediating Na~ influx in excitable cells such as nerve and muscle. ...Dear Editor, Voltage-gated sodium （Nav） channels are membrane pro- teins that are responsible for the propagation of action potentials in mammals by mediating Na~ influx in excitable cells such as nerve and muscle. In human, Nay channels are therapeutic targets as their mutations con- tribute to many diseases. Structures of prokaryotic Nay channels, e.g., NavAb （Payandeh et al., 2011）, NavRh （Zhang et al., 2012） and NavMs （Mccusker et al., 2012）, were successively determined in the past years. Recently, the cryo-EM structures of two eukaryotic Nay channels were reported （Shen et al., 2017; Yan et al., 2017）. Nay channels contain 24 transmembrane helices.展开更多
文摘Voltage-gated sodium （Nav） channels are essential for the rapid upstroke of action potentials and the propa- gation of electrical signals in nerves and muscles. Defects of Nav channels are associated with a variety of channelopathies. More than 1000 disease-related muta- tions have been identified in Nay channels, with Nay1.1 and Nay1.5 each harboring more than 400 mutations. Nay channels represent major targets for a wide array of neurotoxins and drugs. Atomic structures of Nav chan- nels are required to understand their function and dis- ease mechanisms. The recently determined atomic structure of the rabbit voltage-gated calcium （Car） channel Carl.1 provides a template for homology-based structural modeling of the evolutionarily related Nay channels. In this Resource article, we summarized all the reported disease-related mutations in human Nav channels, generated a homologous model of human Nay1.7, and structurally mapped disease-associated mutations. Before the determination of structures of human Nay channels, the analysis presented here serves as the base framework for mechanistic investi- gation of Nav channelopathies and for potential struc- ture-based drug discovery.
基金ACKNOWLEDGEMENTS We apologize to colleagues whose work could not be cited due to the scope of this review. We would like to thank members in Yan laboratory for discussions. We thank Brendan Lehnert, Xinlei Sheng, Quanxiu Li, Dan Ma and Xinhui Zhou for critical reading. This work was supported by funds from the National Basic Research Program （973 Program） （No. 2011CB910501）, the National Natural Science Foundation of China （Grant Nos. 31321062-20131319400, 31125009, and 91017011 ）, and funds from Tsinghua-Peking Center for Life Sciences. The research of N.Y. was supported in part by an International Early Career Scientist grant from the Howard Hughes Medical Institute.
文摘Transcription activator-like （TAL） effectors specifically bind to double stranded （ds） DNA through a central domain of tandem repeats. Each TAL effector （TALE） repeat comprises 33-35 amino acids and recognizes one specific DNA base through a highly variable residue at a fixed position in the repeat. Structural studies have revealed the molecular basis of DNA recognition by TALE repeats. Examination of the overall structure reveals that the basic building block of TALE protein, namely a helical hairpin, is one-helix shifted from the previously defined TALE motif. Here we wish to suggest a structure-based re-demarcation of the TALE repeat which starts with the residues that bind to the DNA backbone phosphate and concludes with the base-rec- ognition hyper-variable residue. This new numbering system is consistent with the （=-solenoid superfamily to which TALE belongs, and reflects the structural integrity of TAL effectors. In addition, it confers integral number of TALE repeats that matches the number of bound DNA bases. We then present fifteen crystal structures of engineered dHax3 variants in complex with target DNA molecules, which elucidate the structural basis for the recognition of bases adenine （A） and guanine （G） by reported or uncharacterized TALE codes. Finally, we analyzed the sequence-structure correlation of the amino acid residues within a TALE repeat. The structural analyses reported here may advance the mechanistic understanding of TALE proteins and facilitate the design of TALEN with improved affinity and specificity.
基金This work was funded by the National Natural Science Foundation of China （Program No. 31200567）, the Fundamental Research Funds for the Central Universities （Program No. 2014JQ001）, and the Huazhong Agricultural University Scientific ＆ Technological Self-innovation Foundation （Program No. 2013RC013）.ACKNOWLEDGMENTS No conflict of interest declared.
文摘Manipulation of gene expression through targeting specific DNA or RNA sequences is a significant challenge, tn the past decade, transcription activator-like （TAL） effectors and zinc fingers （ZFs） have been successfully developed into useful tools for DNA recognition （Bogdanove and Voytas, 2011; Deng et al., 2012a, 2012b）. However, little progress has been made in the realm of RNA targeting due to the lack of understanding about the modular RNA recognition mechanism.
文摘Dear Editor,L-Fucose(6-deoxy-L-galactose,fucose)is the basic compone nt of a variety of glyca n structures.The fucosylated oligosaccharides participate in a variety of cellular activities,like the cell-cell recognition,selectin-mediated leukocyteendothelial adhesion and the formation of Lewis blood group antigens(Ma et al.,2006).GDP-fucose is an important fucose donor in the process of fucosylated oligosaccharides formation.Two pathways of GDP-fucose synthesis are present in the cytosol of mammalian cells,including the de novo pathway and the salvage pathway(Becker et al.,2003).In the salvage pathway,cells use fucose from the extracellular or lysosomal sources to synthesize GDP-fucose.
基金We gratefully thank Dr. Huaizong Shen and Dr. Gaoxingyu Huang for their assistance in preparing the figure of the electron density map of NavPaS. This work was supported by the National Natural Science Foundation of China （Grant Nos. 31670723 and 31621092） and by the funds from the Ministry of Science and Technology of China （No. 2015CB910100） as well as the Beijing Advanced Innovation Center for Structural Biology.
文摘Dear Editor, Voltage-gated sodium （Nav） channels are membrane pro- teins that are responsible for the propagation of action potentials in mammals by mediating Na~ influx in excitable cells such as nerve and muscle. In human, Nay channels are therapeutic targets as their mutations con- tribute to many diseases. Structures of prokaryotic Nay channels, e.g., NavAb （Payandeh et al., 2011）, NavRh （Zhang et al., 2012） and NavMs （Mccusker et al., 2012）, were successively determined in the past years. Recently, the cryo-EM structures of two eukaryotic Nay channels were reported （Shen et al., 2017; Yan et al., 2017）. Nay channels contain 24 transmembrane helices.
