The Saccharomyces cerevisiae Hrq1 and Pif1 DNA helicases synergistically modulate telomerase activity in vitro [Enzymology]

August 1st, 2018 by David G. Nickens, Cody M. Rogers, Matthew L. Bochman

Telomere length homeostasis is vital to maintaining genomic stability and is regulated by multiple factors, including telomerase activity and DNA helicases. The Saccharomyces cerevisiae Pif1 helicase was the first discovered catalytic inhibitor of telomerase, but recent experimental evidence suggests that Hrq1, the yeast homolog of the disease-linked human RecQ-like helicase 4 (RECQL4), plays a similar role via an undefined mechanism. Using yeast extracts enriched for telomerase activity and an in vitro primer extension assay, here we determined the effects of recombinant wild-type and inactive Hrq1 and Pif1 on total telomerase activity and telomerase processivity. We found that titrations of these helicases alone have equal-but-opposite biphasic effects on telomerase, with Hrq1 stimulating activity at high concentrations. When the helicases were combined in reactions, however, they synergistically inhibited or stimulated telomerase activity depending on which helicase was catalytically active. These results suggest that Hrq1 and Pif1 interact and that their concerted activities ensure proper telomere length homeostasis in vivo. We propose a model in which Hrq1 and Pif1 cooperatively contribute to telomere length homeostasis in yeast.

[ASAP] <italic toggle=”yes”>In Vitro</italic> Transcription Networks Based on Hairpin Promoter Switches

July 31st, 2018 by Shaunak Kar, Andrew D. Ellington

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ACS Synthetic Biology
DOI: 10.1021/acssynbio.8b00172
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Gramibactin is a bacterial siderophore with a diazeniumdiolate ligand system

July 30th, 2018 by Ron Hermenau

Gramibactin is a bacterial siderophore with a diazeniumdiolate ligand system

Gramibactin is a bacterial siderophore with a diazeniumdiolate ligand system, Published online: 30 July 2018; doi:10.1038/s41589-018-0101-9

Plant-associated rhizosphere bacteria produce gramibactin, a cyclic lipodepsipeptide siderophore that tightly binds iron via an unexpected functional group, the N-nitrosohydroxylamine (diazeniumdiolate) moieties of the amino acid graminine.
  • Posted in Nat Chem Biol, Publications
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A multicolor riboswitch-based platform for imaging of RNA in live mammalian cells

July 30th, 2018 by Esther Braselmann

A multicolor riboswitch-based platform for imaging of RNA in live mammalian cells

A multicolor riboswitch-based platform for imaging of RNA in live mammalian cells, Published online: 30 July 2018; doi:10.1038/s41589-018-0103-7

A new riboswitch-based RNA sensor called Riboglow binds to quenched fluorescent probes to induce fluorescence turn-on. Riboglow enables tagging and tracking of mRNA and short noncoding RNAs with different colored fluorophores in live mammalian cells.
  • Posted in Nat Chem Biol, Publications
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Monitoring hippocampal glycine with the computationally designed optical sensor GlyFS

July 30th, 2018 by William H. Zhang

Monitoring hippocampal glycine with the computationally designed optical sensor GlyFS

Monitoring hippocampal glycine with the computationally designed optical sensor GlyFS, Published online: 30 July 2018; doi:10.1038/s41589-018-0108-2

A genetically encoded FRET-based optical sensor generated from a computational design approach can monitor hippocampal glycine levels in brain tissue to determine differences between spines and shafts and changes induced by high- and low-frequency stimulation.
  • Posted in Nat Chem Biol, Publications
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Designed peptides that assemble into cross-α amyloid-like structures

July 30th, 2018 by Shao-Qing Zhang

Designed peptides that assemble into cross-α amyloid-like structures

Designed peptides that assemble into cross-α amyloid-like structures, Published online: 30 July 2018; doi:10.1038/s41589-018-0105-5

Structural analysis reveals how certain designed peptides adopt unusual spiraling cross-α amyloid-like structures and also rearrange to helical polymers upon mutation of small nonpolar residues that are critical for packing and stabilization.
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[ASAP] Robustness of a Reconstituted <italic toggle=”yes”>Escherichia coli</italic> Protein Translation System Analyzed by Computational Modeling

July 25th, 2018 by Tomoaki Matsuura, Kazufumi Hosoda, Yoshihiro Shimizu

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ACS Synthetic Biology
DOI: 10.1021/acssynbio.8b00228
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The molecular language of membraneless organelles [Cell Biology]

July 25th, 2018 by Edward Gomes, James Shorter

Eukaryotic cells organize their intracellular components into organelles that can be membrane-bound or membraneless. A large number of membraneless organelles, including nucleoli, Cajal bodies, P-bodies, and stress granules, exist as liquid droplets within the cell and arise from the condensation of cellular material in a process termed liquid-liquid phase separation (LLPS). Beyond a mere organizational tool, concentrating cellular components into membraneless organelles tunes biochemical reactions and improves cellular fitness during stress. In this review, we provide an overview of the molecular underpinnings of the formation and regulation of these membraneless organelles. This molecular understanding explains emergent properties of these membraneless organelles and shines new light on neurodegenerative diseases, which may originate from disturbances in LLPS and membraneless organelles.

[ASAP] Investigation of Solvent Hydron Exchange in the Reaction Catalyzed by the Antibiotic Resistance Protein Cfr

July 22nd, 2018 by Matthew R. Bauerle, Tyler L. Grove, Squire J. Booker

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Biochemistry
DOI: 10.1021/acs.biochem.8b00347

[ASAP] Tight Translational Control Using Site-Specific Unnatural Amino Acid Incorporation with Positive Feedback Gene Circuits

July 19th, 2018 by Yusuke Kato

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ACS Synthetic Biology
DOI: 10.1021/acssynbio.8b00204
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