chapter  15
32 Pages

Applications of Lipidic Cubic Phases in Structural Biology

Compatibility with Membrane Proteins ........................... 426 15.3 Spectroscopy on Proteins Solubilized

in Lipidic Cubic Phases ..................................................... 429 15.4 Crystallization of Soluble and Membrane

Proteins in Lipidic Cubic Phases ...................................... 431 15.5 High-Resolution Structures of Membrane

Proteins from Lipidic Cubic Phase-Grown Crystals ....... 436 15.5.1 Bacteriorhodopsin ................................................ 436

15.5.1.1 K Intermediate................................... 441 15.5.1.2 L Intermediate ................................... 443 15.5.1.3 M Intermediate .................................. 444

15.5.2 Halorhodopsin ...................................................... 445 15.5.3 Sensory Rhodopsin II .......................................... 448

15.5.3.1 K Intermediate................................... 449 15.5.4 Sensory Rhodopsin II-Transducer

II Complex............................................................ 450 15.5.5 Photosynthetic Reaction Center ......................... 450

15.6 Conclusions ......................................................................... 451

Acknowledgments........................................................................... 451 References....................................................................................... 452

The last decades have witnessed remarkable progress in the methods for elucidating structures of biological macromolecules, including x-ray crystallography, NMR spectroscopy, and electron microscopy. Powerful tools such as third-generation synchrotron facilities and high field magnets, and novel experimental methodologies in combination with software development and advanced computing systems, have provided biologists the necessary technological foundation to elucidate novel structures of ever-larger systems at very high resolution. This development is manifested in the exponential growth of the number of structures deposited in the protein data bank (http://www.rcsb.org/pdb), currently exceeding 21,000, which is about ten times the number that was available one decade ago. With the current rate of thousands of new structures per year, and in light of the promise of an even higher rate of structure solution due to “structural genomics” initiatives, it is expected that this exponential growth will continue in the years to come, reinforcing the important role of structural biology in modern life science.