How does radiation damage in protein crystals depend on X-ray dose?
Is radiation damage to cryopreserved protein crystals strictly proportional to accumulated dose at the high-flux density of beams from undulators at third-generation synchrotron sources? The answer is "yes," for overall damage to several different kinds of protein crystals at flux densities up to 10(15) ph/sec/mm(2) (APS beamline 19-ID). We find that, at 12 keV (1 A wavelength), about ten absorbed photons are sufficient to "kill" a unit cell. As this corresponds to about one elastically scattered photon, each unit cell can contribute only about one photon to total Bragg diffraction. The smallest crystal that can yield a full data set to 3.5 A resolution has a diameter of about 20 microm (100 A unit cell).
Sliz
Piotr
P
Department of Biological Chemistry and Molecular Pharmacology, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115, USA.
Harrison
Stephen C
SC
Rosenbaum
Gerd
G
D015925:Cryopreservation; D018360:Crystallography, X-Ray; D004307:Dose-Response Relationship, Radiation; D016356:Gene Products, tax / Q000737:chemistry; D015789:HLA-A2 Antigen / Q000737:chemistry; D046911:Macromolecular Substances; D008562:Membrane Glycoproteins / Q000737:chemistry; D011506:Proteins / Q000737:chemistry / Q000528:radiation effects*; D014759:Viral Envelope Proteins; D014764:Viral Proteins / Q000737:chemistry; D014965:X-Rays
D016356:Gene Products, tax; D015789:HLA-A2 Antigen; D046911:Macromolecular Substances; D008562:Membrane Glycoproteins; D011506:Proteins; C118670:US2 protein, Varicellovirus; D014759:Viral Envelope Proteins; D014764:Viral Proteins