Circadian regulation: Switching periods

June 20th, 2017 by Grant Miura

Nature Chemical Biology 13, 693 (2017). doi:10.1038/nchembio.2426

Author: Grant Miura

Synthetic biology: Playing favorites

June 20th, 2017 by Ross Cloney

Nature Chemical Biology 13, 693 (2017). doi:10.1038/nchembio.2425

Author: Ross Cloney

Nucleation and growth of a bacterial functional amyloid at single-fiber resolution

June 19th, 2017 by Mike Sleutel

Nature Chemical Biology 13, 902 (2017). doi:10.1038/nchembio.2413

Authors: Mike Sleutel, Imke Van den Broeck, Nani Van Gerven, Cécile Feuillie, Wim Jonckheere, Claire Valotteau, Yves F Dufrêne & Han Remaut

  • Posted in Nat Chem Biol, Publications
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Cpf1 proteins excise CRISPR RNAs from mRNA transcripts in mammalian cells

June 19th, 2017 by Guocai Zhong

Nature Chemical Biology 13, 839 (2017). doi:10.1038/nchembio.2410

Authors: Guocai Zhong, Haimin Wang, Yujun Li, Mai H Tran & Michael Farzan

Cpf1 is a CRISPR effector protein that has greater specificity than Streptococcus pyogenes Cas9 (SpCas9) in genome-editing applications. Here we show that Lachnospiraceae bacterium (Lb) and Acidaminococus sp. (As) Cpf1 orthologs have RNase activities that can excise multiple CRISPR RNAs (crRNAs) from a single RNA polymerase II–driven RNA transcript expressed in mammalian cells. This property simplifies modification of multiple genomic targets and can be used to increase the efficiency of Cpf1-mediated editing.

  • Posted in Nat Chem Biol, Publications
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A heme-dependent enzyme forms the nitrogen–nitrogen bond in piperazate

June 19th, 2017 by Yi-Ling Du

Nature Chemical Biology 13, 836 (2017). doi:10.1038/nchembio.2411

Authors: Yi-Ling Du, Hai-Yan He, Melanie A Higgins & Katherine S Ryan

Molecules containing a nitrogen–nitrogen (N–N) linkage have a variety of structures and biological activities; however, no enzyme has yet been demonstrated to catalyze N–N bond formation in an organic molecule. Here we report that the heme-dependent enzyme KtzT from Kutzneria sp. 744 catalyzes N–N bond formation in the biosynthesis of piperazate, a building block for nonribosomal peptides.

  • Posted in Nat Chem Biol, Publications
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A scaffold protein that chaperones a cysteine-sulfenic acid in H2O2 signaling

June 19th, 2017 by Antoine Bersweiler

Nature Chemical Biology 13, 909 (2017). doi:10.1038/nchembio.2412

Authors: Antoine Bersweiler, Benoît D'Autréaux, Hortense Mazon, Alexandre Kriznik, Gemma Belli, Agnès Delaunay-Moisan, Michel B Toledano & Sophie Rahuel-Clermont

  • Posted in Nat Chem Biol, Publications
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A water-soluble DsbB variant that catalyzes disulfide-bond formation in vivo

June 19th, 2017 by Dario Mizrachi

Nature Chemical Biology 13, 1022 (2017). doi:10.1038/nchembio.2409

Authors: Dario Mizrachi, Michael-Paul Robinson, Guoping Ren, Na Ke, Mehmet Berkmen & Matthew P DeLisa

  • Posted in Nat Chem Biol, Publications
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Iron Transport Proteins: Gateways of Cellular and Systemic Iron Homeostasis [Cell Biology]

June 16th, 2017 by Mitchell D. Knutson

Cellular iron homeostasis is maintained by iron and heme transport proteins that work in concert with ferrireductases, ferroxidases, and chaperones to direct the movement of iron into, within, and out of cells. Systemic iron homeostasis is regulated by the liver-derived peptide hormone, hepcidin. The interface between cellular and systemic iron homeostasis is readily observed in the highly dynamic iron handling of four main cell types: duodenal enterocytes, erythrocyte precursors, macrophages, and hepatocytes. This review provides an overview of how these cell types handle iron, highlighting how iron and heme transporters mediate the exchange and distribution of body iron in health and disease.

A ciliary opsin in the brain of a marine annelid zooplankton is UV-sensitive and the sensitivity is tuned by a single amino acid residue [Molecular Biophysics]

June 16th, 2017 by Hisao Tsukamoto, I-Shan Chen, Yoshihiro Kubo, Yuji Furutani

Ciliary opsins were classically thought to function only in vertebrates for vision, but they have been recently identified also in invertebrates for non-visual photoreception. Larvae of the annelid Platynereis dumerilii are used as a zooplankton model, and this zooplankton species possesses a "vertebrate-type" ciliary opsin (named c-opsin) in the brain. Platynereis c-opsin is suggested to relay light signals to melatonin production and circadian behaviors. Thus, the spectral and biochemical characteristics of this c-opsin would be directly related to non-visual photoreception in this zooplankton model. Here, we demonstrate that the c-opsin can sense UV to activate intracellular signaling cascades, and that it can directly bind exogenous all-trans-retinal. These results suggest that this c-opsin regulates circadian signaling in a UV-dependent manner and that it does not require supply of 11-cis-retinal for photoreception. Avoidance of damaging UV irradiation is a major cause of a large-scale daily zooplankton movement, and the observed capability of the c-opsin to transmit UV signals and bind all-trans-retinal is ideally suited for sensing UV radiation in the brain, which presumably lacks enzymes producing 11-cis-retinal. Mutagenesis analyses indicated that a unique amino acid residue (Lys-94) is responsible for c-opsin-mediated UV sensing in the Platynereis brain. We therefore propose that acquisition of the lysine residue in the c-opsin would be a critical event in the evolution of Platynereis to enable detection of ambient UV. In summary, our findings indicate that the c-opsin possesses spectral and biochemical properties suitable for UV sensing by the zooplankton model.
  • Posted in Journal of Biological Chemistry, Publications
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Two Dynamical Regimes of the Substrate Radical Rearrangement Reaction in B12-Dependent Ethanolamine Ammonia-Lyase Resolve Contributions of Native Protein Configurations and Collective Configurational Fluctuations to Catalysis

June 15th, 2017 by Meghan Kohne, Chen Zhu and Kurt Warncke

TOC Graphic

Biochemistry
DOI: 10.1021/acs.biochem.7b00294