Binding analysis with purified bacterial receptor distinguishes two structural domains in cyclic AMP (cAMP). The first, the cyclic phosphate and furanose, constitutes a binding domain. This region is bound tightly to the receptor. The rest of cAMP is not bound; the adenine moiety of cAMP is exposed. Unlike binding, activity of cAMP requires the adenine moiety. To be active, cAMP must have in domain II the base adenine - specifically, its Watson-Crick atoms N-1 and N6. Analysis of indoleacetic acid, a compound able to replace cAMP at the L-arabinose operon, indicates a similar distinction between binding and active domains. To be active, the indole must have substitution (carboxyl or amide) electronically comparable to the cAMP N-1 and N-6. On this basis, the authors propose a detailed mechanism of action of cAMP (or indoleacetic acid) in E. coli. They propose that the exposed adenine of cAMP enters into the DNA. This interaction destabilizes the DNA. It enhances transcription. Marked similarities indicate an identical mechanism for the steroid hormones in eukaryotes.
|Original language||English (US)|
|Number of pages||5|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|Issue number||7 I|
|State||Published - 1981|
All Science Journal Classification (ASJC) codes