Phase determination by multiple-wavelength X-ray diffraction: crystal structure of a basic "blue" copper protein from cucumbers
1988
Guss, J.M. | Merritt, E.A. | Phizackerley, R.P. | Hedman, B. | Murata, M. | Hodgson, K.O. | Freeman, H.C.
A novel x-ray diffraction technique, multiple-wavelength anomalous dispersion (MAD) phasing, has been applied to the de novo determination of an unkown protein structure, that of the "blue" copper protein isolated from cucumber seedlings. This method makes use of crystallographic phases determined from measurements made at several wavelengths and has recently been made technically feasible through the use of intense, polychromatic synchrotron radiation together with accurate data collection from multiwire electronic area detectors. In contrast with all of the conventional methods of solving protein structures, which require either multiple isomorphous derivatives or coordinates of a similar structure for molecular replacement, this technique allows direct solution of the classical "phase problem" in x-ray crystallography. MAD phase assignment should be particularly useful for determining structures of small to medium-sized metallo-proteins for which isomorphous derivatives are difficult or impossible to make. The structure of this particular protein provides new insights into the spectroscopic and redox properties of blue copper proteins, an important class of metalloproteins widely distributed in nature.
显示更多 [+] 显示较少 [-]