Li L, Hong R, Hastings J W
Department of Molecular and Cellular Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA 02138-2020, USA.
Proc Natl Acad Sci U S A. 1997 Aug 19;94(17):8954-8. doi: 10.1073/pnas.94.17.8954.
We report a unique case of a gene containing three homologous and contiguous repeat sequences, each of which, after excision, cloning, and expression in Escherichia coli, is shown to code for a peptide catalyzing the same reaction as the native protein, Gonyaulax polyedra luciferase (Mr = 137). This enzyme, which catalyzes the light-emitting oxidation of a linear tetrapyrrole (dinoflagellate luciferin), exhibits no sequence similarities to other luciferases in databases. Sequence analysis also reveals an unusual evolutionary feature of this gene: synonymous substitutions are strongly constrained in the central regions of each of the repeated coding sequences.
我们报告了一个独特的案例，一个基因包含三个同源且相邻的重复序列，每个序列在切除、克隆并在大肠杆菌中表达后，都被证明编码一种肽，该肽催化的反应与天然蛋白多甲藻发光蛋白（Mr = 137）相同。这种酶催化线性四吡咯（甲藻荧光素）的发光氧化反应，在数据库中与其他荧光素酶没有序列相似性。序列分析还揭示了该基因一个不寻常的进化特征：在每个重复编码序列的中心区域，同义替换受到强烈限制。
