Tobin Fricke
University of Californiawith Asmahan Abu-Arish, Dr. Michael Elbaum & Dr. Sharon Wolf
3d reconstruction of a helical protein from electron microscopy
Infection by gene transfer from bacterium to plant
Growth factorEnzymes to produce opines
Can replace with other genes for transformationEvidence for gene transfer to animal cells
Agrobacterium tumefaciens
electron microscopy
• Just like optical microscopy, but with electrons instead of photons
tomography
• by looking through an object at many angles, determine its internal structure.
Helical symmetry
• Translation is equivalent to axial rotation
filament picking tool
automated picking
Results: T-complex structure
hollow helical tube
diameter 16 nmpitch 5.2 nm4.3 VirE2/turnshortening factor ~7
3-domain structure of VirE2
single-strand DNA lies on a shelf at the interior of the tube at radius ~5.5 nm
20 kb ssDNA: ext. length 8. m random coil ~90 nm