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The primary structure of rat ribosomal protein S15a
1Department of Biochemistry and Molecular Biology, University of Chicago, Illinois 60637.
Abstract:
The amino acid sequence of the rat 40S ribosomal subunit protein S15a was deduced from the sequence of nucleotides in two recombinant cDNAs. Ribosomal protein S15a has 129 amino acids, the NH2-terminal methionine is removed after translation of the mRNA and has a molecular weight of 14,698. Hybridization of the cDNA to digests of nuclear DNA suggests that there are 10 to 15 copies of the S15a gene. The mRNA for the protein is about 650 nucleotides in length. Rat S15a is related to ribosomal proteins from other eukaryotes, from eubacteria, and from archaebacteria.
Insights
Researchers determined the amino acid sequence for rat ribosomal protein S15a, finding it has 129 amino acids and is related to similar proteins across different life forms. This study also identified 10-15 gene copies for this essential ribosomal protein.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- Ribosomal proteins are crucial components of ribosomes, the cellular machinery responsible for protein synthesis.
- Understanding the structure and genetics of ribosomal proteins is fundamental to comprehending gene expression and cellular function.
Purpose of the Study:
- To determine the complete amino acid sequence of the rat 40S ribosomal subunit protein S15a.
- To investigate the gene copy number and mRNA characteristics of rat ribosomal protein S15a.
- To explore the evolutionary relationships of rat S15a with ribosomal proteins from diverse organisms.
Main Methods:
- Deduction of amino acid sequence from nucleotide sequences of recombinant cDNAs.
- Analysis of protein molecular weight and post-translational modifications (methionine removal).
- Hybridization of cDNA to nuclear DNA digests to estimate gene copy number.
- Determination of mRNA length.
Main Results:
- The amino acid sequence of rat ribosomal protein S15a was established, revealing a protein of 129 amino acids with a molecular weight of 14,698 Da after removal of the initial methionine.
- The study suggests the presence of 10 to 15 gene copies for the S15a protein in the rat genome.
- The mRNA encoding rat S15a is approximately 650 nucleotides long.
- Rat S15a exhibits sequence homology with ribosomal proteins from eukaryotes, eubacteria, and archaebacteria, indicating evolutionary conservation.
Conclusions:
- The characterization of rat ribosomal protein S15a provides insights into the molecular composition of the 40S ribosomal subunit.
- The findings suggest a conserved evolutionary history for ribosomal proteins across different domains of life.
- This research contributes to the understanding of gene regulation and the structural basis of protein synthesis.