CRYSTAL STRUCTURE OF THE BACTERIAL RIBOSOME FROM ESCHERICHIA COLI IN COMPLEX WITH PAROMOMYCIN AND RIBOSOME RECYCLING FACTOR (RRF). THIS FILE CONTAINS THE 50S SUBUNIT OF THE FIRST 70S RIBOSOME, WITH PAROMOMYCIN AND RRF BOUND. THE ENTIRE CRYSTAL STRUCTURE CONTAINS TWO 70S RIBOSOMES AND IS DESCRIBED IN REMARK 400.