The dawn of dominance by the mature domain in tRNA splicing.
The relationship between enzyme architecture and substrate specificity among archaeal pre-tRNA splicing endonucleases has been investigated more deeply, by using biochemical assays and model building. The enzyme from Archeoglobus fulgidus (AF) is particularly interesting: it cleaves the bulge-helix-bulge target without requiring the mature tRNA domain, but, when the target is a bulge-helix-loop, the mature domain is required. A model of AF based on its electrostatic potential shows three polar patches interacting with the pre-tRNA substrate. A simple deletion mutant of the AF endonuclease lacking two of the three polar patches no longer cleaves the bulge-helix-loop substrate with or without the mature domain. This single deletion shows a possible path for the evolution of eukaryal splicing endonucleases from the archaeal enzyme.
Tocchini-Valentini
Giuseppe D
GD
Istituto di Biologia Cellulare, Consiglio Nazionale delle Ricerche, Campus A, Buzzati-Traverso, Via Ramarini 32, Monterotondo Scalo, 00016 Rome, Italy.
Fruscoloni
Paolo
P
Tocchini-Valentini
Glauco P
GP
D000595:Amino Acid Sequence; D019843:Archaeal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D019611:Archaeoglobus fulgidus / Q000201:enzymology; D001483:Base Sequence; D001665:Binding Sites; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012326:RNA Splicing / Q000235:genetics*; D012343:RNA, Transfer / Q000737:chemistry* / Q000235:genetics*; D055672:Static Electricity; D040681:Structural Homology, Protein; D013379:Substrate Specificity
D019843:Archaeal Proteins; D012343:RNA, Transfer