11/2011 - Cryoelectron tomography of radial spokes in cilia and flagella

Radial spokes (RSs) are ubiquitous components in the 9 + 2 axoneme thought to be mechanochemical transducers involved in local control of dynein-driven microtubule sliding. They are composed of >23 polypeptides, whose interactions and placement must be deciphered to understand RS function. In this paper, we show the detailed three-dimensional (3D) structure of RS in […]

Read more

11/2010 - Three-dimensional structural analysis of eukaryotic flagella/cilia by electron cryo-tomography

Electron cryo-tomography is a potential approach to analyzing the three-dimensional conformation of frozen hydrated biological macromolecules using electron microscopy. Since projections of each individual object illuminated from different orientations are merged, electron tomography is capable of structural analysis of such heterogeneous environments as in vivo or with polymorphism, although radiation damage and the missing wedge are severe […]

Read more

10/2010 - The archaeo-eukaryotic primase of plasmid pRN1 requires a helix bundle domain for faithful primer synthesis

The plasmid pRN1 encodes for a multifunctional replication protein with primase, DNA polymerase and helicase activity. The minimal region required for primase activity encompasses amino-acid residues 40-370. While the N-terminal part of that minimal region (residues 47-247) folds into the prim/pol domain and bears the active site, the structure and function of the C-terminal part […]

Read more

10/2010 - Molecular basis of RNA polymerase III transcription repression by Maf1

RNA polymerase III (Pol III) transcribes short RNAs required for cell growth. Under stress conditions, the conserved protein Maf1 rapidly represses Pol III transcription. We report the crystal structure of Maf1 and cryo-electron microscopic structures of Pol III, an active Pol III-DNA-RNA complex, and a repressive Pol III-Maf1 complex. Binding of DNA and RNA causes […]

Read more

10/2009 - Simultaneous alignment of dual-axis tilt series

We present a strategy for the alignment of dual-axis tomographic series, based on reference points and simultaneous alignment of both series. Each series is first aligned individually, an affine transformation is determined to bring the two series in a unique reference system, and all experimental coordinates are combined in a single system of equations. In […]

Read more