ANOMALOUS-DISPERSION WITH EDGES IN THE SOFT-X-RAY REGION - FIRST RESULTS OF DIFFRACTION FROM SINGLE-CRYSTALS OF RIBOSOMES NEAR THE K-ABSORPTION EDGE OF PHOSPHORUS

X-ray diffraction from a single crystal of the small ribosomal subunit of Thermus thermophilus was measured at five wavelengths near the K-a bsorption edge of phosphorus. The intensity of the low-order diffracti on peaks varies strongly with the wavelength. It is influenced by the dispersion of contrast due to the P atoms of the ribosomal ribonucleic acid and by that of absorption, in comparable amounts.