Structure of a bacterial 30S ribosomal subunit at 5.5 angstrom resolution

The 30S ribosomal subunit binds messenger RNA and the anticodon stem-loop o f transfer RNA during protein synthesis. A crystallographic analysis of the structure of the subunit from the bacterium Thermos thermophilus is presen ted, At a resolution of 5.5 Angstrom, the phosphate backbone of the ribosom al RNA is visible, as are the cu-helices of the ribosomal proteins, enablin g double-helical regions of RNA to be identified throughout the subunit, al l seven of the small-subunit proteins of known crystal structure to be posi tioned in the electron density map, and the fold of the entire central doma in of the small-subunit ribosomal RNA to be determined.