Beuve A, Danchin A
Institut Pasteur, Paris, France.
J Mol Biol. 1992 Jun 20;225(4):933-8. doi: 10.1016/0022-2836(92)90093-y.
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.
腺苷酸环化酶和鸟苷酸环化酶具有不同但相关的底物，是研究底物识别的范例。筛选了一个与真核生物对应基因在系统发育上相关的原核生物腺苷酸环化酶基因，以寻找重塑该酶特异性的突变体。第一步，选择了一个显示出显著水平鸟苷酸环化酶活性的突变体。这是由于一个点突变破坏了大部分腺苷酸环化酶活性。第二步筛选恢复了大部分原始活性。这是由于同一区域的另一个突变，从而首次鉴定出腺苷酸环化酶和鸟苷酸环化酶中的一个功能域。
