IN-VITRO ASSEMBLY OF A RIBONUCLEOPROTEIN PARTICLE CORRESPONDING TO THE PLATFORM DOMAIN OF THE 30S RIBOSOMAL-SUBUNIT

A fragment of the 16S RNA of Thermus thermophilus corresponding to the central domain (nucleotides 547-895) has been prepared by transcripti on in vitro. Incubation of this fragment with the total 30S ribosomal proteins has resulted in the formation of a compact 12S ribonucleoprot ein particle, This particle contained five T. thermophilus proteins co rresponding to Escherichia coli ribosomal proteins S6, S8, S11, S15, a nd possibly Sis, all of which were previously shown to interact with t he central domain of the 16S RNA and to be localized in the platform ( side bulge) of the 30S ribosomal subunit, When examined by electron mi croscopy, isolated particles have an appearance that is similar in siz e and shape to the corresponding morphological features of the 30S sub unit, We conclude that the central domain of the 16S RNA can independe ntly and specifically assemble with a defined subset of ribosomal prot eins into a compact ribonucleoprotein particle corresponding to the pl atform (side bulge) of the 30S subunit.