Volume 26 Issue 12, December 2019

Volume 26 Issue 12

Opening up T-box RNA

Structural elucidation of T-box–tRNA complexes provides new insights into the mechanisms of tRNA decoding and aminoacylation sensing by T-box riboswitches.

See Li, Su et al., Battaglia et al., Suddala and Zhang

Image: composite by Erin Dewalt using image from Yevgen Romanenko / Moment / Getty and structures of T-box–tRNA complex in ribbon representation prepared by Jacob Weaver and Alexander Serganov. Cover Design: Erin Dewalt.

News & Views

  • News & Views |

    Bacterial T-boxes are regulatory mRNA regions that control the transcription or translation of factors involved in amino acid supply. T-boxes act by directly binding to non-aminoacylated tRNA in response to amino acid starvation. Three studies now capture three-dimensional structures of tRNA–T-box complexes and reveal a set of RNA features that are required for the recognition of specific tRNAs and modulation of gene expression.

    • Jacob W. Weaver
    •  & Alexander Serganov
  • News & Views |

    Finally, the architecture of the translocase of the mitochondrial outer membrane (TOM complex) is revealed, after 20 years of anticipation. Two groups have now determined the near-atomic structures of the TOM complex. These findings improve understanding of the mechanisms by which TOM facilitates the passage of about 1,000 different proteins from the cytosol into the mitochondria.

    • Doron Rapaport
  • News & Views |

    Chromatin is compartmentalized spatially and temporally at multiple levels, but the precise organization of chromatin and mechanisms underlying its restructuring remain unclear. Two studies published in Cell and Nature now demonstrate the ability of chromatin to undergo liquid–liquid phase separation under physiological conditions and show that this intrinsic physicochemical property of chromatin can be regulated.

    • Yi Zhang
    •  & Tatiana G. Kutateladze
  • News & Views |

    Stabilization of the 3D genome architecture surrounding DNA lesions is critical for the maintenance of genome integrity. A new report by Ochs et al. shows how 53BP1 and RIF1 assemble a higher-order structure in the vicinity of damaged chromatin to protect it from unscheduled DNA-end resection.

    • Indrajeet Ghodke
    •  & Evi Soutoglou

Brief Communications

  • Brief Communication |

    The structure of human SMG1–SMG8–SMG9, a PI(3)K-related protein kinase complex central to mRNA surveillance, uncovers an InsP6-binding site in the SMG1 kinase that is conserved in mTOR and important for kinase activity.

    • Yair Gat
    • , Jan Michael Schuller
    • , Mahesh Lingaraju
    • , Elisabeth Weyher
    • , Fabien Bonneau
    • , Mike Strauss
    • , Peter J. Murray
    •  & Elena Conti

Articles

  • Article |

    Cocrystal and cryo-EM structures of Geobacillus kaustophilus glyQ and Bacillus subtilis glyQS T-box-tRNA complexes establish a universal mechanism of amino acid sensing on tRNAs and gene regulation by T-box riboswitches.

    • Shuang Li
    • , Zhaoming Su
    • , Jean Lehmann
    • , Vassiliki Stamatopoulou
    • , Nikoleta Giarimoglou
    • , Frances E. Henderson
    • , Lixin Fan
    • , Grigore D. Pintilie
    • , Kaiming Zhang
    • , Muyuan Chen
    • , Steven J. Ludtke
    • , Yun-Xing Wang
    • , Constantinos Stathopoulos
    • , Wah Chiu
    •  & Jinwei Zhang
  • Article |

    The cryo-EM structure of a megacomplex between chimeric GPCR, G protein and β-arrestin in their canonical active conformations provides insight into the basis of sustained G protein signaling upon megacomplex internalization.

    • Anthony H. Nguyen
    • , Alex R. B. Thomsen
    • , Thomas J. Cahill III
    • , Rick Huang
    • , Li-Yin Huang
    • , Tara Marcink
    • , Oliver B. Clarke
    • , Søren Heissel
    • , Ali Masoudi
    • , Danya Ben-Hail
    • , Fadi Samaan
    • , Venkata P. Dandey
    • , Yong Zi Tan
    • , Chuan Hong
    • , Jacob P. Mahoney
    • , Sarah Triest
    • , John Little IV
    • , Xin Chen
    • , Roger Sunahara
    • , Jan Steyaert
    • , Henrik Molina
    • , Zhiheng Yu
    • , Amedee des Georges
    •  & Robert J. Lefkowitz
  • Article |

    Biochemical and structural analysis demonstrate that simultaneous detection of poly-lysine in the exit tunnel and poly(A) in the decoding center allows ribosomes to detect aberrant mRNAs, stall elongation and trigger downstream quality control pathways.

    • Viswanathan Chandrasekaran
    • , Szymon Juszkiewicz
    • , Junhong Choi
    • , Joseph D. Puglisi
    • , Alan Brown
    • , Sichen Shao
    • , V. Ramakrishnan
    •  & Ramanujan S. Hegde
  • Article |

    Oligomers of human αA-crystallin are characterized structurally via a hybrid approach, combining cryo-EM, cross-linking/mass spectrometry, NMR and modeling, providing insight into their dynamic behavior and heterogeneity and revealing that oxidized oligomers can also act as chaperones.

    • Christoph J. O. Kaiser
    • , Carsten Peters
    • , Philipp W. N. Schmid
    • , Maria Stavropoulou
    • , Juan Zou
    • , Vinay Dahiya
    • , Evgeny V. Mymrikov
    • , Beate Rockel
    • , Sam Asami
    • , Martin Haslbeck
    • , Juri Rappsilber
    • , Bernd Reif
    • , Martin Zacharias
    • , Johannes Buchner
    •  & Sevil Weinkauf
  • Article |

    Cryo-EM structures of MERS-CoV S glycoprotein trimer in complex with different sialosides reveal how the virus engages with sialylated receptors, providing insight into receptor specificity and selectivity.

    • Young-Jun Park
    • , Alexandra C. Walls
    • , Zhaoqian Wang
    • , Maximillian M. Sauer
    • , Wentao Li
    • , M. Alejandra Tortorici
    • , Berend-Jan Bosch
    • , Frank DiMaio
    •  & David Veesler
  • Article |

    Cryo-EM resolution of HIV-1 Env trimer bound to CD4 and a tyrosine-sulfated, coreceptor-mimicking antibody reveals two configurations of gp120–gp41 protomers that create asymmetric Env trimer conformations on the path to membrane fusion.

    • Zhi Yang
    • , Haoqing Wang
    • , Albert Z. Liu
    • , Harry B. Gristick
    •  & Pamela J. Bjorkman
  • Article |

    Cryo-EM structure of the C-terminal domain of human APOBEC3F in complex with HIV-1 Vif and CFBβ, along with functional analyses, reveals how Vif targets a host restriction protein.

    • Yingxia Hu
    • , Belete A. Desimmie
    • , Henry C. Nguyen
    • , Samantha J. Ziegler
    • , Tat Cheung Cheng
    • , John Chen
    • , Jia Wang
    • , Hongwei Wang
    • , Kai Zhang
    • , Vinay K. Pathak
    •  & Yong Xiong

Amendments & Corrections