Operons bacterial

An excellent source for reviews of many bacterial operons. The Web-based version, EcoSal, is updated regularly. 

BG Hall. Directed evolution of a bacterial operon. BioEssays 12 551-558, 1990. 

Yanofsky C. Attenuation in the control of expression of bacterial operons. Nature. 1981 289 751-758. 

Some archaeal r-protein operons contain open reading frames (ORFs) that are not present in the equivalent bacterial operon. In many cases, these ORFs code for proteins which show sequence similarity to eucaryal r-proteins. For example, ORF c, d and e in the spc operon of Methanococcus vannielii [100] and Sulfolobus acidocaldarius [Kusser et al., unpublished] code for r-proteins equivalent to the eucaryal r-proteins S4 Rattus norwegicus), L32 Homo sapiens) and LI9 R. norwegicus) respectively. 

Some bacterial operons are regulated solely by attenuation without repressor-operator interactions. 

In E. coli, about half the genes are clustered into oper-ons each of which encodes enzymes involved in a particular metabolic pathway or proteins that interact to form one multisubunit protein. For instance, the trp operon mentioned earlier encodes five enzymes needed in the biosynthesis of tryptophan (see Figure 4-12). Similarly, the lac operon encodes three enzymes required for the metabolism of lactose, a sugar present in milk. Since a bacterial operon is tran-... 

The cluster of genes that form a bacterial operon comprises a single transcription unit, which Is transcribed from a particular promoter Into a single primary transcript. In other words, genes and transcription units often are distinguish-... 

Fig. 14.6. Bacterial operon. A cistron encodes a single polyrpeptide chain. In bacteria, a single promoter may control transcription of an operon containing many cistrons. A single pxjlycistronic mRNA is transcribed. Its translation produces a number of polypeptide chains.

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