Reconstructing the evolutionary history of the artiodactyl ribonuclease superfamily

• Published in: Nature (London) Vol. 374; no. 6517; pp. 57 - 59
• Main Authors: Jermann, Thomas M, Opitz, Jochen G, Stackhouse, Joseph, Benner, Steven A
• Format: Journal Article
• Language: English
• Published: London Nature Publishing 02.03.1995; Nature Publishing Group
• Subjects: Amino Acid Sequence; Animals; Artiodactyla; Artiodactyla - classification; Artiodactyla - genetics; Artiodactyla - metabolism; Biochemistry; Biological and medical sciences; Biological Evolution; Catalysis; Classical genetics, quantitative genetics, hybrids; Digestion; Enzyme Stability; Evolution; Fundamental and applied biological sciences. Psychology; Genetics of eukaryotes. Biological and molecular evolution; Mammals; Molecular Sequence Data; Mutagenesis, Site-Directed; Proteins; Recombinant Proteins; Ribonucleases - genetics; Ribonucleases - metabolism; Ribonucleic acid; RNA; RNA - metabolism; RNA, Double-Stranded - metabolism; Vertebrata; Molecular evolution; Vertebrata; Mammalia; Enzymatic activity; Enzyme; Hydrolases; Esterases; Artiodactyla; Phylogeny; Pancreatic ribonuclease; Ungulata
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/374057a0

The sequences of proteins from ancient organisms can be reconstructed from the sequences of their descendants by a procedure that assumes that the descendant proteins arose from the extinct ancestor by the smallest number of independent evolutionary events ('parsimony'). The reconstructed sequences can then be prepared in the laboratory and studied. Thirteen ancient ribonucleases (RNases) have been reconstructed as intermediates in the evolution of the RNase protein family in artiodactyls (the mammal order that includes pig, camel, deer, sheep and ox). The properties of the reconstructed proteins suggest that parsimony yields plausible ancient sequences. Going back in time, a significant change in behaviour, namely a fivefold increase in catalytic activity against double-stranded RNA, appears in the RNase reconstructed for the founding ancestor of the artiodactyl lineage, which lived about 40 million years ago. This corresponds to the period when ruminant digestion arose in the artiodactyls, suggests that contemporary artiodactyl digestive RNases arose from a non-digestive ancestor, and illustrates how evolutionary reconstructions can help in the understanding of physiological function within a protein family.