Folding of homologous proteins the re folding of different rnase species is independent of sequence variations proline content and glycosylation
Krebs, H.; Schmid, F.X.; Jaenicke, R.
Journal of Molecular Biology 169(2): 619-636
1983
ISSN/ISBN: 0022-2836 Accession: 005474348
The refolding kinetics of 4 different pancreatic RNases were compared. Bovine and ovine RNase contain 4 proline residues, red deer RNase has 5 prolines, the enzyme from roe deer 6 prolines. Despite the variation in the amount of prolines, all 4 proteins show a constant value of 20% fast refolding species UF. The extra proline residues of the deer enzymes do not increase the amount of slow refolding species US. Consequently these residues may be non-essential for folding. Despite many differences in the amino acid sequence, the rates of the fast and slow refolding reactions are very similar for all investigated RNases, indicating that the pathway of refolding has been conserved during evolution, i.e., the positions where amino acid substitutions occur are not critically important for the rate-determining steps of the folding process. A carbohydrate chain attached to RNase does not alter the folding properties of the protein: RNase A and RNase B from roe deer show identical refolding kinetics.