Morphology remodelling and membrane channel formation in synthetic cells via reconfigurable DNA nanorafts.

The shape of biological matter is central to cell function at different length scales and determines how cellular components recognize, interact and respond to one another. However, their shapes are often transient and hard to reprogramme. Here we construct a synthetic cell model composed of signal-responsive DNA nanorafts, biogenic pores and giant unilamellar vesicles (GUVs).

3D DNA origami pincers that multitask on giant unilamellar vesicles.

Proteins self-assemble to function in living cells. They may execute essential tasks in the form of monomers, complexes, or supramolecular cages via oligomerization, achieving a sophisticated balance between structural topology and functional dynamics. The modularity and programmability make DNA origami unique in mimicking these key features.

New insights into the structure and dynamics of the TOM complex in mitochondria.

To date, there is no general physical model of the mechanism by which unfolded polypeptide chains with different properties are imported into the mitochondria. At the molecular level, it is still unclear how transit polypeptides approach, are captured by the protein translocation machinery in the outer mitochondrial membrane, and how they subsequently cross the entropic barrier of a protein translocation pore to enter the intermembrane space. This deficiency has been due to the lack of detailed structural and dynamic information about the membrane pores.

Tracking the Activity and Position of Mitochondrial β-Barrel Proteins.

Total interference reflection fluorescence (TIRF) microscopy of lipid bilayers is an effective technique for studying the lateral movement and ion channel activity of single integral membrane proteins. Here we describe how to integrate the mitochondrial outer membrane preprotein translocase TOM-CC and its β-barrel protein-conducting channel Tom40 into supported lipid bilayers to identify possible relationships between movement and channel activity. We propose that our approach can be readily applied to membrane protein channels where transient tethering to either membrane-proximal or intramembrane structures is accompanied by a change in channel permeation.

Two conformations of the Tom20 preprotein receptor in the TOM holo complex.

The TOM complex is the main entry point for precursor proteins (preproteins) into mitochondria. Preproteins containing targeting sequences are recognized by the TOM complex and imported into mitochondria. We have determined the structure of the TOM core complex from by single-particle electron cryomicroscopy at 3.