The preliminary sequence of tRNA Met F from Anacystis nidulans compared with other initiator tRNAs

Organization and sequence of five tRNA genes and of an unidentified reading frame in the wheat chloroplast genome: evidence for gene rearrangements during the evolution of chloroplast genomes

The genes for the initiator tRNA(Met)CAU, tRNA(Gly)UCC, tRNA(Thr)GGU, tRNA(Glu)UUC and tRNA(Tyr)GUA and an open reading frame of 62 codons have been identified by sequencing a 2,358 bp BamHI and a 1,378 bp BamHI-Sst2 DNA fragments from wheat chloroplasts. A comparison of the organization of these five tRNA genes and of the open reading frame on the wheat, tobacco and spinach chloroplast genomes suggests that at least three genomic inversions must have occurred during the evolution of the wheat chloroplast genome from a spinach-like ancestor genome. Furthermore, it seems that in wheat the 91 bp intergenic region between the genes for the initiator tRNA(Met) and the gene for tRNA(Gly)UCC is one end-point of the 20 kbp genomic inversion proposed by Palmer and Thompson in the case of maize (Palmer and Thompson 1982). A 119 bp duplication is located at this junction: the first copy comprises the 91 bp of the intergenic region and the first 28 bp of the tRNA(Met) gene, the second copy is found downstream of the tRNA(Met) gene.

The complete nucleotide sequence of a 23S rRNA gene from a blue-green alga, Anacystis nidulans

The complete nucleotide sequence of a 23S rRNA gene from a blue-green alga, Anacystis nidulans, has been determined. This nucleotide sequence has 78% and 68% homologies with those of the tobacco chloroplast and Escherichia coli 23S rRNA genes, respectively. The 3'-terminal region of the A. nidulans 23S rRNA gene has strong homology with the chloroplast 4.5S rRNA.

RNA structure

This review is concerned primarily with the physical structure and changes in the structure of RNA molecules. It will be evident that we have not attempted comprehensive coverage of what amounts to a vast literature. We have tried to stay away from particular areas that have been recently reviewed elsewhere. Citations to and information from them are included, however, so that access to the literature is available. Much of what we treat in depth deals with the crystal structures and solution behaviour of model RNA compounds, including synthetic polymers and molecular fragments such as dinucleoside phosphates. Sequence data on natural RNA are cited, but not in detail. Similarly, apart from tRNA, natural RNAs the structural determinations of which are presently not so far advanced, are not dwelt upon. We have tried to present in detail the available structural data with scaled drawings that permit facile comparisons of molecular geometries.