These patterns can be translated into an image of the molecule's atomic structure. In recent years, however, the availability of third-generation synchrotron light sources has enabled researchers to overcome these difficulties. An energy range of from 3.5 to 15 keV, over which the wavelength is tunable, allows for data collection from crystals with large unit cells, from microcrystals, and from weakly diffracting crystals. Two programs in the research of biomolecular complexes, the 70S Ribosome and Wnt Receptor Pathway, have benefited from these techniques and provide data on unique biomolecular crystal samples. 70S Ribosome Working at the MCF, a team of researchers from the University of California at Santa Cruz and Berkeley Lab, headed by Dr. Harry Noller, a professor of molecular biology at UC Santa Cruz, recently succeeded in imaging the structure of the 70S ribosome of the bacterium Thermus thermophilus at a resolution of 7.8 angstroms.
Ribosomes are tiny granules present in large numbers in the cytoplasm of cells.
Efforts to solve the structure of the ribosome have been going on for four decades, but until recently were hampered by the complexity of the molecule, the difficulty of growing ribosome crystals, and a shortage of data on which to build. The new model of the 70S ribosome suggests how the transfer RNA interacts with the ribosome and how the 50S and 30S subunits interact with one another. It is also clear that most of the excitement of figuring the molecular mechanism of translation lies ahead. The outer membrane of a cell is a thin wall of fatty molecules embedded with thousands of proteins, some of which regulate the flow of materials in and out of the cell, while others are receptors of chemical signals or messages from other cells. The Wnt proteins are a family of secreted glycoproteins that bind to the outside of the cell at transmembrane receptors to transduce a signal across the cell membrane.