scholarly journals A viral genome packaging motor transitions between cyclic and helical symmetry to translocate dsDNA

2020 ◽  
Author(s):  
Michael Woodson ◽  
Joshua Pajak ◽  
Wei Zhao ◽  
Wei Zhang ◽  
Gaurav Arya ◽  
...  
Keyword(s):  
Chromosome Segregation ◽  
Molecular Motors ◽  
Viral Genome ◽  
Quaternary Structure ◽  
Common Mechanism ◽  
Mitochondrial Membranes ◽  
Genome Packaging ◽  
Helical Symmetry ◽  
Experimental Systems ◽  
Ring Conformations

SUMMARYMolecular segregation and biopolymer manipulation require the action of molecular motors to do work by applying directional forces to macromolecules. The additional strand conserved E (ASCE) ring motors are an ancient family of molecular motors responsible for diverse tasks ranging from biological polymer manipulation (e.g. protein degradation and chromosome segregation) to establishing and maintaining proton gradients across mitochondrial membranes. Viruses also utilize ASCE segregation motors to package their genomes into their protein capsids and serve as accessible experimental systems due to their relative simplicity. We show by CryoEM focused image reconstruction that ASCE ATPases in viral dsDNA packaging motors adopt helical symmetry complementary to their dsDNA substrates. Together with previous data, including structural results showing these ATPases in planar ring conformations, our results suggest that these motors cycle between helical and planar cyclical symmetry, providing a possible mechanism for directional translocation of DNA. We further note that similar changes in quaternary structure have been observed for proteasome and helicase motors, suggesting an ancient and common mechanism of force generation that has been adapted for specific tasks over the course of evolution.

scholarly journals A viral genome packaging motor transitions between cyclic and helical symmetry to translocate dsDNA

2021 ◽  
Vol 7 (19) ◽  
pp. eabc1955
Author(s):  
Michael Woodson ◽  
Joshua Pajak ◽  
Bryon P. Mahler ◽  
Wei Zhao ◽  
Wei Zhang ◽  
...  
Keyword(s):  
Image Reconstruction ◽  
Molecular Motors ◽  
Viral Genome ◽  
Quaternary Structure ◽  
Force Generation ◽  
Common Mechanism ◽  
Genome Packaging ◽  
Helical Symmetry ◽  
Experimental Systems ◽  
Double Stranded Dna

Molecular segregation and biopolymer manipulation require the action of molecular motors to do work by applying directional forces to macromolecules. The additional strand conserved E (ASCE) ring motors are an ancient family of molecular motors responsible for diverse biological polymer manipulation tasks. Viruses use ASCE segregation motors to package their genomes into their protein capsids and provide accessible experimental systems due to their relative simplicity. We show by cryo-EM–focused image reconstruction that ASCE ATPases in viral double-stranded DNA (dsDNA) packaging motors adopt helical symmetry complementary to their dsDNA substrates. Together with previous data, our results suggest that these motors cycle between helical and planar configurations, providing a possible mechanism for directional translocation of DNA. Similar changes in quaternary structure have been observed for proteasome and helicase motors, suggesting an ancient and common mechanism of force generation that has been adapted for specific tasks over the course of evolution.

scholarly journals Viral genome packaging terminase cleaves DNA using the canonical RuvC-like two-metal catalysis mechanism

2017 ◽  
pp. gkw1354 ◽  
Author(s):  
Rui-Gang Xu ◽  
Huw T. Jenkins ◽  
Maria Chechik ◽  
Elena V. Blagova ◽  
Anna Lopatina ◽  
...  
Keyword(s):  
Viral Genome ◽  
Genome Packaging ◽  
Metal Catalysis ◽  
Catalysis Mechanism

Function of a viral genome packaging motor from bacteriophage T4 is insensitive to DNA sequence

2021 ◽  
Author(s):  
Douglas E. Smith ◽  
Youbin E. Mo ◽  
Nick Keller ◽  
Damian delToro ◽  
Neeti Ananthaswamy ◽  
...  
Keyword(s):  
Dna Sequence ◽  
Viral Genome ◽  
Bacteriophage T4 ◽  
Genome Packaging

scholarly journals Parts list for a microtubule depolymerising kinesin

2018 ◽  
Vol 46 (6) ◽  
pp. 1665-1672 ◽  
Author(s):  
Claire T. Friel ◽  
Julie P. Welburn
Keyword(s):  
Chromosome Segregation ◽  
Molecular Motors ◽  
Neuronal Development ◽  
Current Understanding ◽  
Cellular Functions ◽  
Microtubule Cytoskeleton ◽  
Microtubule Binding ◽  
Large Group ◽  
Kinesin Superfamily ◽  
Different Parts

The Kinesin superfamily is a large group of molecular motors that use the turnover of ATP to regulate their interaction with the microtubule cytoskeleton. The coupled relationship between nucleotide turnover and microtubule binding is harnessed in various ways by these motors allowing them to carry out a variety of cellular functions. The Kinesin-13 family is a group of specialist microtubule depolymerising motors. Members of this family use their microtubule destabilising activity to regulate processes such as chromosome segregation, maintenance of cilia and neuronal development. Here, we describe the current understanding of the structure of this family of kinesins and the role different parts of these proteins play in their microtubule depolymerisation activity and in the wider function of this family of kinesins.

scholarly journals Insights into Specific DNA Recognition during the Assembly of a Viral Genome Packaging Machine

2002 ◽  
Vol 9 (5) ◽  
pp. 981-991 ◽  
Author(s):  
Tonny de Beer ◽  
Jenny Fang ◽  
Marcos Ortega ◽  
Qin Yang ◽  
Levi Maes ◽  
...  
Keyword(s):  
Viral Genome ◽  
Dna Recognition ◽  
Genome Packaging ◽  
Packaging Machine

scholarly journals Energy-Independent Helicase Activity of a Viral Genome Packaging Motor

Biochemistry ◽  
2011 ◽  
Vol 51 (1) ◽  
pp. 391-400 ◽  
Author(s):  
Jenny R. Chang ◽  
Benjamin T. Andrews ◽  
Carlos E. Catalano
Keyword(s):  
Viral Genome ◽  
Helicase Activity ◽  
Genome Packaging

scholarly journals Intrinsically disordered region of influenza A NP regulates viral genome packaging via interactions with viral RNA and host PI(4,5)P 2

Virology ◽  
2016 ◽  
Vol 496 ◽  
pp. 116-126 ◽  
Author(s):  
Michinori Kakisaka ◽  
Kazunori Yamada ◽  
Akiko Yamaji-Hasegawa ◽  
Toshihide Kobayashi ◽  
Yoko Aida
Keyword(s):  
Viral Genome ◽  
Influenza A ◽  
Viral Rna ◽  
Genome Packaging ◽  
Intrinsically Disordered ◽  
Intrinsically Disordered Region

scholarly journals Condensin DC spreads linearly and bidirectionally from recruitment sites to create loop-anchored TADs in C. elegans

2021 ◽  
Author(s):  
David Sebastian Jimenez ◽  
Jun Kim ◽  
Bhavana Ragipani ◽  
Bo Zhang ◽  
Lena Annika Street ◽  
...  
Keyword(s):  
Chromosome Segregation ◽  
X Chromosome ◽  
Molecular Motors ◽  
Sequence Motif ◽  
X Chromosomes ◽  
C Elegans ◽  
Eukaryotic Chromosome ◽  
Multiple Copies

AbstractCondensins are molecular motors that compact DNA for chromosome segregation and gene regulation. In vitro experiments have begun to elucidate the mechanics of condensin function but how condensin loading and translocation along DNA controls eukaryotic chromosome structure in vivo remains poorly understood. To address this question, we took advantage of a specialized condensin, which organizes the 3D conformation of X chromosomes to mediate dosage compensation (DC) in C. elegans. Condensin DC is recruited and spreads from a small number of recruitment elements on the X chromosome (rex). We found that ectopic insertion of rex sites on an autosome leads to bidirectional spreading of the complex over hundreds of kilobases. On the X chromosome, strong rex sites contain multiple copies of a 12-bp sequence motif and act as TAD borders. Inserting a strong rex and ectopically recruiting the complex on the X chromosome or an autosome creates a loop-anchored TAD. Unlike the CTCF system, which controls TAD formation by cohesin, direction of the 12-bp motif does not control the specificity of loops. In an X;V fusion chromosome, condensin DC linearly spreads into V and increases 3D DNA contacts, but fails to form TADs in the absence of rex sites. Finally, we provide in vivo evidence for the loop extrusion hypothesis by targeting multiple dCas9-Suntag complexes to an X chromosome repeat region. Consistent with linear translocation along DNA, condensin DC accumulates at the block site. Together, our results support a model whereby strong rex sites act as insulation elements through recruitment and bidirectional spreading of condensin DC molecules and form loop-anchored TADs.

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