Volume 27 Issue 3, March 2020

Many AAA+ ATPases assemble as hexamers to unfold protein substrates using a hand-over-hand, threading mechanism, but the Bcs1 AAA+ ATPase facilitates mitochondrial membrane translocation of the folded iron–sulfur Rieske protein. Two reports reveal that Bcs1 adopts an unusual heptameric configuration and provide insights into a non-canonical translocation mechanism.

Recent studies report the first structures of two CALHM family members, describing unexpected oligomeric architecture and providing insights into the mechanism of function of CALHM channels.

A 3.3-Å-resolution cryo-EM structure of yeast Maf1 bound to RNA polymerase III (Pol III) explains the molecular mechanism for Pol III inhibition.

Structural analysis reveals that ATP-binding and Smc1–Smc3 heterodimerization promotes conformational changes within the cohesin ATPase that are transmitted to the Smc coiled-coil domains, leading to ring opening at the Smc3–Scc1 interface.

Structural analysis of the DNA crosslink repair factors FANCD2 and FANCI demonstrates that a complex of both factors adopts a closed conformation upon ubiquitination of FANCD2, trapping the complex on DNA.

Using computational, spectroscopic and in vivo approaches, two short motifs in the N-terminal region of human α-synuclein are shown to be critical for toxic protein aggregation but also for membrane fusion.

The RNA-binding protein SRSF7 autoregulates its protein levels through an intricate negative feedback mechanism that involves translation of two distinct protein halves, termed Split-ORFs; the potential to encode Split-ORFs is also seen in other targets of nonsense-mediated decay.

Cryo-EM structure of the human PAC1R receptor bound to its neuropeptide ligand PACAP and to an engineered G_s complex reveals the mode of PACAP recognition and suggests functional diversity of the extracellular domains in class B GPCRs.

Structural and binding studies show that a repeated peptide motif in the N-terminal domain of CsoS2 mediates multivalent interactions with assembled Rubisco to facilitate its encapsulation into the carboxysome.

Structural elucidation of the pore form of binary Iota toxin Ib with its toxic subunit, Ia, visualizes interactions mediating Ia translocation through the pore and extension of the Ia N-terminus consistent with a Brownian ratchet translocation mechanism.

thCHART, a hybridization capture approach using biotinylated LNA-oligonucleotides with toehold architecture, improves the specificity of RNA enrichment and enables detection of the chromosomal spreading pattern of Drosophila roX2 lncRNA under different cellular conditions.