Volume 08, No.2
March issue 2003
1. SPring-8の現状／PRESENT STATUS OF SPring-8
MEXT National Project on Protein and Functional Analysis in Japan
2. 最近の研究から／FROM LATEST RESEARCH
Accurate Structural Analysis of Disordered Materials with High-Energy X-ray Diffraction
(財)高輝度光科学研究センター 放射光研究所 JASRI Synchrotron Radiation Research Laboratory
日本原子力研究所 関西研究所 放射光科学研究センター Synchrotron Radiation Research Center, JAERI Kansai Research Establishment
- With the arrival of the latest generation of synchrotron sources and the introduction of advanced insertion devices (wigglers and undulators), the high-energy (E >=30 keV) X-ray diffraction technique has become feasible, leading to new approaches in the quantitative study of the structure of disordered materials. High-energy X-ray diffraction has several advantages: higher resolution in real space due to a wide range of scattering vector Q, smaller correction terms (especially the absorption correction), reduction of truncation errors, the feasibility of running under extreme environments, including high-temperatures and high-pressures, and the ability to make direct comparisons between X-ray and neutron diffraction data. Recently, high-energy X-ray diffraction data have been combined with neutron diffraction data from a pulsed source to provide more detailed and reliable structural information than that hitherto available. This article reviews and summarizes recent results obtained from the high-energy X-ray diffraction on glass, liquid, amorphus and crystalline materials using bending magnet beamlines at SPring-8.
(財)高輝度光科学研究センター 利用研究促進部門Ⅱ JASRI Life and Environment Science Division
- By using the combination of intense X-ray beams from an undulator-based beamline at SPring-8 (BL45XU) and a microbeam optics, we were able to record X-ray diffraction patterns from single myofibrils of a striated muscle (bumblebee flight muscle). Unlike in the conventional method, the muscle cell was irradiated end-on, so that a diffraction pattern from a myofibril was recorded without isolating it from the cell. The recorded pattern consisted of a number of hexagonally arranged spot-like reflections, clearly indicating that the reflections originated from a single hexagonal lattice of myofilaments. Since the muscle cells used were ~3 mm long and contained 1000+ sarcomeres connected in series, the result means that the lattices in these sarcomeres are exactly in register. The achievement opens the possibility that the X-ray diffraction technique may be applied to other micrometer-sized protein assemblies in the cell, such as axonemes and mitotic spindles.
3. 研究会等報告／WORKSHOP AND COMMITTEE REPORT
RIKEN Symposium on Structural Biology (VIII)
“Structural Biology of Protein Complexes : from Structure to Mechanisms”