Molecular evolution of pancreatic-type ribonucleases

Area of Science:

• Evolutionary biology
• Molecular biology
• Biochemistry

Background:

• Ribonucleases (RNases) are enzymes crucial for RNA metabolism.
• Understanding the evolutionary relationships of RNases provides insights into mammalian diversification.

Purpose of the Study:

• To construct evolutionary trees for mammalian ribonucleases using amino acid sequences.
• To compare messenger RNA sequences of different species.
• To investigate the evolutionary relationships between mammalian, reptilian, and human RNase families.

Main Methods:

• Maximum parsimony analysis of 39 mammalian ribonuclease amino acid sequences.
• Comparison of nucleic acid sequences of rat pancreatic and bovine seminal ribonuclease messengers.
• Sequence comparison of turtle pancreatic ribonuclease and human angiogenin with mammalian ribonucleases.

Main Results:

• Phylogenetic trees largely align with established mammalian biological classifications.
• Edentates and primates show early divergence patterns within eutherian mammals.
• Identified a conserved second stop codon in messenger RNAs and homologous active-site regions in nonsecretory RNases.
• Turtle RNase and human angiogenin exhibit significant sequence divergence but share structural features with mammalian RNases.

Conclusions:

• Amino acid sequence analysis supports the evolutionary relationships of mammalian ribonucleases.
• Conserved structural and sequence features indicate functional importance and shared ancestry.
• Comparative analysis highlights evolutionary divergence and conservation across different species and RNase types.