From adenylate cyclase to guanylate cyclase. Mutational analysis of a change in substrate specificity.
Adenylate and guanylate cyclases, having different but related substrates, are a paradigm for the study of substrate discrimination. A prokaryotic adenylate cyclase gene, phylogenetically related to eukaryotic counterparts, was screened for mutants remodelling the enzyme's specificity. In a first step, a mutant was selected displaying a significant level of guanylate cyclase activity. This was due to a point mutation destroying most of the adenylate cyclase activity. A second selection step restored most of the original activity. This resulted from an additional mutation in the same region, thus permitting the first identification of a functional domain in adenylate and guanylate cyclases.
Institut Pasteur, Paris, France.
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Danchin
D000262:Adenylyl Cyclases / Q000235:genetics* / Q000378:metabolism*; D000595:Amino Acid Sequence; D001483:Base Sequence; D005798:Genes, Bacterial; D006162:Guanylate Cyclase / Q000235:genetics* / Q000378:metabolism*; D007700:Kinetics; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010957:Plasmids; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D016962:Sinorhizobium meliloti / Q000201:enzymology / Q000235:genetics; D013379:Substrate Specificity; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
D011993:Recombinant Fusion Proteins; D001616:beta-Galactosidase; D000262:Adenylyl Cyclases; D006162:Guanylate Cyclase