A three-dimensional model of domain III of the Escherichia coli small ribosomal subunit.

A three-dimensional model of domain III (nucleotides 920 to 1395) of the 30S ribosomal subunit of E. coli is proposed. The data used as a guide in folding the secondary structure of the RNA into a tertiary structure are four long range RNA-RNA interactions proposed by us on the basis of experiments performed in this laboratory plus two sets of data from other laboratories: protein-RNA cross-linking sites for proteins S1, S3, S7, S10 and S12, and the interprotein distances determined by neutron scattering.

Identification of the collar-like structure of the 30S ribosomal subunit from E. coli by dark field electron microscopy.

We have used dark field electron microscopy to study a fragment of the small (30S) subunit of the E. coli ribosome. This fragment is almost the same size as the parent particle but RNA sequencing studies have shown it to lack, as a major constituent, a 150-nucleotide stretch at the 3' end of the rRNA, and two minor sections constituting 20 nucleotides from the 5' end and the 15 nucleotides of the sequence 687-701.

Long range RNA-RNA interactions in the 30 S ribosomal subunit of E. coli.

We have attempted to identify long-range interactions in the tertiary structure of RNA in the E. coli 30 S ribosome. Native subunits were cleaved with ribonuclease and separated into nucleoprotein fragments which were deproteinized and fractionated into multi-oligonucleotide complexes under conditions intended to preserve RNA-RNA interactions.

Specific visualization of ribosomal RNA in the intact ribosome by electron spectroscopic imaging.

The recently developed electron microscopic technique of electron spectroscopic imaging has been used to map the distribution of phosphorus, and therefore of RNA, in situ in the ribosomal subunits of E. coli. The results indicate that the RNA moiety of both subunits is concentrated toward the centre of the particle somewhat more than is the total mass, but reaches the outer surface at several places.

A survey of 50 S ribosomal subunits by dark field electron microscopy.

A survey of dark field electron micrographs of the 50 S ribosomal subunit of E. coli has been performed and supplemented, for comparative purposes, by examination of negatively stained or metal shadowed specimens in the bright field mode. Attention was directed to the so-called "crown" and "kidney" views.