FLUORESCENT X-RAY INTERFERENCE FROM A PROTEIN MONOLAYER

Fluorescent x-ray interference patterns have been observed from monola yers of both a metal-containing protein (ferritin) and a nonmetal-cont aining protein [bovine serum albumin (BSA)] bound on a gold substrate. These interference patterns have been used to determine structure dat a. The nonmetal-containing protein was first reacted with metal ions b y means of a chelate compound to place the necessary chromophore in th e molecule. The size of the ferritin core measured by a scanning elect ron microscope agrees with the value obtained from the x-ray interfere nce experiments. In the BSA molecule, the measured interference fringe is consistent with the model in which the short axes of BSA molecules are perpendicular to the surface substrate.