Resource for the Visualization of Biological Complexity (RVBC)
Ryanodine Receptor Isoform 3 in Closed and Open States
This animation switches between open and closed configurations of the ryanodine receptor (isoform 3) to illustrate the structural rearrangements that occur during the transition. The ryanodine receptor functions as an intracellular calcium release channel in many cells, particularly excitable cells such as muscle. The lower part of the structure comprises the transmembrane regions of the receptor and the upper part is cytoplasmic. Movements of protein mass occur in both of these regions. The figures to the right show static views of the receptor in the two states. For more details see Sharma et al. (2000) J. Biol. Chem. 275:9485.
Data provided by Dr. Terence Wagenknecht
Frozen-Hydrated Rat Liver Mitochondrion
3D model of the membranes in an isolated rat liver mitochondrion (0.7 micron diam. x 0.5 micron thick) embedded in vitreous ice by plunge freezing. Most of the cristae contained in this mitochondrion are represented. Towards the end of the clip, arrows point to 4 of the narrow openings that attach the cristae to the peripheral inner membrane. The model comes from Mannella et al. (2001) IUBMB Life, 52: 93-100.
Data provided by Dr. Carmen Mannella
Elongation Cycle of Protein Biosynthesis
An animated display of the E. coli ribosome and its interactions with the tRNA and the elongation factors during the elongation cycle, in the course of which the polypeptide chain is elongated by the addition of one amino acid. The ribosome is represented by the experimental density map at 11.5 Å resolution (from Gabashvili et al. (2000) Cell 100, 537-549), while the tRNA and the elongation factors are represented by their space-filling atomic models. The positions of the ligands are based on cryo-EM reconstructions of various ribosome-ligand complexes; for details, see Frank et al. (1999), J. Struct. Biol., 128: 15-18.
Data provided by Dr. Joachim Frank
The Ribosome: A Molecular Ratchet
The movie juxtaposes two cryo-EM density maps, one obtained from the ribosome bound with elongation factor EF-G in the presence of a nonhydrolyzable GTP analog, the other from the ribosome bound with P-site tRNA as a control. It is evident that the small subunit rotates with respect to the large subunit, and both undergo a major structural reorganization. The motion accompanies translocation, the process by which the tRNAs are moved from the A- and P- to the P- and E-sites, respectively, and mRNA is moved to the next codon. For details, see Frank and Agrawal (2000), Nature, 406: 318-322.