Volume 22 Issue 9, September 2015

Volume 22 Issue 9

The dimeric transmembrane protein PsbS plays a key role in plant photoprotection. Crystallographic and biochemical analyses provide insight into PsbS pH-dependent activation. Cover image by © AlexPro9500/iStock/Thinkstock (pp 729–735, News and Views (p 650)

News and Views

  • News & Views |

    Export of effector proteins is crucial for the virulence program of the malaria parasite Plasmodium falciparum. A crystal structure of the Plasmodium vivax processing enzyme essential for protein export reveals noncanonical aspartic protease features and provides an avenue for antimalarial drug development.

    • Daniel E Goldberg
  • News & Views |

    Totipotency, the ability of early embryonic cells to generate a complete adult organism as well as extraembryonic tissue, is a fleeting property found only in very early embryonic cells. A breakthrough study now shows that inhibition of DNA replication–linked nucleosome assembly causes embryonic stem cells to resemble totipotent cells. Notably, inhibition of chromatin assembly stimulates reprogramming during somatic-cell nuclear transfer experiments.

    • Paul D Kaufman
  • News & Views |

    Plants protect themselves from fluctuating high-light conditions by dissipating a large part of their absorbed energy as heat, in a process that requires the protein PsbS. The structure of PsbS opens new possibilities for understanding the mechanism of photoprotection in plants.

    • Roberta Croce
  • News & Views |

    The eukaryotic 26S proteasome is responsible for degrading virtually any protein with an appropriate ubiquitin signal, and in the process ubiquitin is spared and recycled. Two studies of the proteasome-associated deubiquitinase UBP6 now shed light on how deubiquitination coordinates the cycle of substrate processing.

    • Tingting Yao
  • News & Views |

    Two studies using chromosome conformation capture (3C) analyses in the Gram-positive bacterium Bacillus subtilis have revealed a global pattern of chromosome organization that originates from loading sites of the Smc–ScpAB complex. Loading Smc–ScpAB at a single genomic location is sufficient to promote genome-wide folding of DNA into a well-defined structure.

    • Frank Bürmann
    •  & Stephan Gruber

Perspective

  • Perspective |

    New methods permit genomic mapping of oxidized methylcytosines at single-base resolution and suggest new regulatory functions for 5-methylcytocine (5mC) derivatives 5hmC, 5fC and 5caC in the mammalian genome.

    • Hao Wu
    •  & Yi Zhang

Articles

  • Article |

    New data show that depletion of histone chaperone CAF-1 in mouse embryonic stem (ES) cells induces early embryonic-like cells that exhibit gene-expression patterns and reprogramming efficiencies characteristic of 2-cell-stage populations that arise spontaneously in ES-cell culture, thus suggesting that altered chromatin assembly contributes to differences in stem-cell plasticity.

    • Takashi Ishiuchi
    • , Rocio Enriquez-Gasca
    • , Eiji Mizutani
    • , Ana Bošković
    • , Celine Ziegler-Birling
    • , Diego Rodriguez-Terrones
    • , Teruhiko Wakayama
    • , Juan M Vaquerizas
    •  & Maria-Elena Torres-Padilla
  • Article |

    The Mycobacterium tuberculosis necrotizing toxin (TNT) is shown to cause toxicity by hydrolyzing NAD+ in the host cell. The crystal structure of TNT bound to its immunity factor reveals a new NAD+ glycohydrolase fold.

    • Jim Sun
    • , Axel Siroy
    • , Ravi K Lokareddy
    • , Alexander Speer
    • , Kathryn S Doornbos
    • , Gino Cingolani
    •  & Michael Niederweis
  • Article |

    Extensive mutant cycle analysis provides a map of the residues that contribute to stability and activation-associated conformational dynamics of the Gαi1 protein in nucleotide-bound states and in complex with the G protein–coupled receptor rhodopsin.

    • Dawei Sun
    • , Tilman Flock
    • , Xavier Deupi
    • , Shoji Maeda
    • , Milos Matkovic
    • , Sandro Mendieta
    • , Daniel Mayer
    • , Roger J P Dawson
    • , Gebhard F X Schertler
    • , M Madan Babu
    •  & Dmitry B Veprintsev
  • Article |

    Mig6 phosphorylation at two consecutive tyrosines induces rearrangements that lead to Mig6 sticking to and inhibiting the same EGFR that catalyzed its phosphorylation. This mechanism may serve as a basis for inhibition of oncogenic EGFR variants.

    • Eunyoung Park
    • , Nayoung Kim
    • , Scott B Ficarro
    • , Yi Zhang
    • , Byung Il Lee
    • , Ahye Cho
    • , Kihong Kim
    • , Angela K J Park
    • , Woong-Yang Park
    • , Bradley Murray
    • , Matthew Meyerson
    • , Rameen Beroukhim
    • , Jarrod A Marto
    • , Jeonghee Cho
    •  & Michael J Eck
  • Article |

    Electron microscopy and biochemistry analyses reveal that the deubiquitinase Ubp6, in its ubiquitin-bound form, inhibits substrate deubiquitination by Rpn11, stabilizes the proteasome in a substrate-engaged conformation and interferes with the engagement of a subsequent substrate.

    • Charlene Bashore
    • , Corey M Dambacher
    • , Ellen A Goodall
    • , Mary E Matyskiela
    • , Gabriel C Lander
    •  & Andreas Martin
  • Article |

    Biochemical and structural analyses show that Rubisco accumulation factor 1 (Raf1) stabilizes RbcL dimers, which then assemble into octamers. Raf1 is then displaced by RbcS, thus yielding the Rubisco holoenzyme.

    • Thomas Hauser
    • , Javaid Y Bhat
    • , Goran Miličić
    • , Petra Wendler
    • , F Ulrich Hartl
    • , Andreas Bracher
    •  & Manajit Hayer-Hartl
  • Article |

    PsbS is a transmembrane photosystem II protein essential for photoprotection in plants. Crystal structures show that PsbS is not a canonical pigment-binding protein and provide insights into its pH-dependent activation mechanism.

    • Minrui Fan
    • , Mei Li
    • , Zhenfeng Liu
    • , Peng Cao
    • , Xiaowei Pan
    • , Hongmei Zhang
    • , Xuelin Zhao
    • , Jiping Zhang
    •  & Wenrui Chang
  • Article |

    O-GlcNAcylation is a post-translational modification catalyzed by O-GlcNAc transferase. Here, a high-throughput activity assay combined with mass spectrometric and crystallographic analyses sheds light on the substrate recognition and specificity of O-GlcNAc transferase.

    • Shalini Pathak
    • , Jana Alonso
    • , Marianne Schimpl
    • , Karim Rafie
    • , David E Blair
    • , Vladimir S Borodkin
    • , Alexander W Schüttelkopf
    • , Osama Albarbarawi
    •  & Daan M F van Aalten