Assembly of the Xrn2/Rat1-Rai1-Rtt103 termination complexes in mesophilic and thermophilic organisms.

The 5'-3' exoribonuclease Xrn2, known as Rat1 in yeasts, terminates mRNA transcription by RNA polymerase II (RNAPII). In the torpedo model of termination, the activity of Xrn2/Rat1 is enhanced by Rai1, which is recruited to the termination site by Rtt103, an adaptor protein binding to the RNAPII C-terminal domain (CTD). The overall architecture of the Xrn2/Rat1-Rai1-Rtt103 complex remains unknown.

Multi-Site Conformational Exchange in the Synthetic Neomycin-Sensing Riboswitch Studied by F NMR.

The synthetic neomycin-sensing riboswitch interacts with its cognate ligand neomycin as well as with the related antibiotics ribostamycin and paromomycin. Binding of these aminoglycosides induces a very similar ground state structure in the RNA, however, only neomycin can efficiently repress translation initiation. The molecular origin of these differences has been traced back to differences in the dynamics of the ligand:riboswitch complexes.

Observation of conformational changes that underlie the catalytic cycle of Xrn2.

Nuclear magnetic resonance (NMR) methods that quantitatively probe motions on molecular and atomic levels have propelled the understanding of biomolecular processes for which static structures cannot provide a satisfactory description. In this work, we studied the structure and dynamics of the essential 100-kDa eukaryotic 5'→3' exoribonuclease Xrn2. A combination of complementary fluorine and methyl-TROSY NMR spectroscopy reveals that the apo enzyme is highly dynamic around the catalytic center.

Correction to: A suite of F based relaxation dispersion experiments to assess biomolecular motions.

In the original publication, Figures 3 and 6 were displayed incorrectly due to a mistake made by the publisher. The correct version of Figs. 3 and 6 are given below.

A suite of F based relaxation dispersion experiments to assess biomolecular motions.

Proteins and nucleic acids are highly dynamic bio-molecules that can populate a variety of conformational states. NMR relaxation dispersion (RD) methods are uniquely suited to quantify the associated kinetic and thermodynamic parameters. Here, we present a consistent suite of F-based CPMG, on-resonance R and off-resonance R RD experiments.

Changes in conformational equilibria regulate the activity of the Dcp2 decapping enzyme.

Crystal structures of enzymes are indispensable to understanding their mechanisms on a molecular level. It, however, remains challenging to determine which structures are adopted in solution, especially for dynamic complexes. Here, we study the bilobed decapping enzyme Dcp2 that removes the 5' cap structure from eukaryotic mRNA and thereby efficiently terminates gene expression.

LEGO-NMR spectroscopy: a method to visualize individual subunits in large heteromeric complexes.

Seeing the big picture: Asymmetric macromolecular complexes that are NMR active in only a subset of their subunits can be prepared, thus decreasing NMR spectral complexity. For the hetero heptameric LSm1-7 and LSm2-8 rings NMR spectra of the individual subunits of the complete complex are obtained, showing a conserved RNA binding site. This LEGO-NMR technique makes large asymmetric complexes accessible to detailed NMR spectroscopic studies.