Related Experiment Videos
Characterization and derivation of the gene coding for mitochondrial carbamyl phosphate synthetase I of rat
Abstract:
The nucleotide sequence of rat carbamyl phosphate synthetase I mRNA has been determined from the complementary DNA. The mRNA comprises minimally 5,645 nucleotides and codes for a polypeptide of 164,564 Da corresponding to the precursor form of the rat liver enzyme. The primary sequence of mature rat carbamyl phosphate synthetase I indicates that the precursor is cleaved at one of two leucines at residues 38 or 39. The derived amino acid sequence of carbamyl phosphate synthetase I is homologous to the sequences of carbamyl phosphate synthetase of Escherichia coli and yeast. The sequence homology extends along the entire length of the rat polypeptide and encompasses the entire sequences of both the small and large subunits of the E. coli and yeast enzymes. The protein sequence data provide strong evidence that the carbamyl phosphate synthetase I gene of rat, the carAB gene of E. coli, and the CPA1 and CPA2 genes of yeast were derived from common ancestral genes. Part of the rat carbamyl phosphate synthetase I gene has been characterized with two nonoverlapping phage clones spanning 28.7 kilobases of rat chromosomal DNA. This region contains 13 exons ranging in size from 68 to 195 base pairs and encodes the 453 carboxyl-terminal amino acids of the rat protein. Southern hybridization analysis of rat genomic DNA indicates the carbamyl phosphate synthetase I gene to be present in single copy.
Insights
Researchers sequenced rat carbamyl phosphate synthetase I (CPS1) mRNA, revealing evolutionary links to microbial enzymes. This CPS1 gene is present in a single copy within the rat genome.
Area of Science:
- Biochemistry
- Molecular Biology
- Genetics
Background:
- Carbamyl phosphate synthetase I (CPS1) is a key enzyme in the urea cycle, primarily found in the liver.
- Understanding the genetic and molecular basis of CPS1 is crucial for metabolic research.
Purpose of the Study:
- To determine the nucleotide sequence of rat CPS1 mRNA.
- To analyze the deduced amino acid sequence and its evolutionary relationship with homologous enzymes in other species.
- To characterize the structure of the rat CPS1 gene in the chromosomal DNA.
Main Methods:
- Complementary DNA (cDNA) sequencing of rat CPS1 mRNA.
- Amino acid sequence analysis and homology comparisons.
- Characterization of rat genomic DNA using phage clones and Southern hybridization.
Main Results:
- The rat CPS1 mRNA sequence (5,645 nucleotides) codes for a 164,564 Da precursor protein.
- The deduced amino acid sequence shows significant homology to CPS1 from Escherichia coli and yeast, suggesting a common ancestral origin.
- A 28.7 kilobase region of the rat CPS1 gene, containing 13 exons, encodes the carboxyl-terminal portion of the protein.
- The CPS1 gene exists as a single copy in the rat genome.
Conclusions:
- The sequence data strongly support the hypothesis that rat CPS1, E. coli carAB, and yeast CPA1/CPA2 genes evolved from common ancestral genes.
- The structural characterization provides insights into the gene organization and evolution of CPS1.