Related Experiment Video
Updated: Aug 18, 2026

Development of a Backbone Cyclic Peptide Library as Potential Antiparasitic Therapeutics Using Microwave Irradiation
Published on: January 27, 2016
The conformational protential of porcine proinsulin C-peptide
Abstract:
Statistical analysis of protein sequences lends itself to the identification of regions with a definite inclination to adopt specific main-chain conformations. Application of the model of Chou and Fasman[1,2] to porcine proinsulin C-peptide localizes the tendency to form a helix in the segments (38 to 44) and (51 to 58). A tendency to beta turn formation is predicted for the segment (45 to 50). The realization of this conformational potential under native and various other conditions was examined by CD spectroscopy. Synthetic C-peptide as well as the synthetic fragments (33 - 40), (41 - 52), (41 - 61), (46 - 52), (46 - 61), and (53 - 61) were included in the study. These fragments provide breaks in the amino acid sequence in each of the potentially ordered regions. The strong helical tendency in the (51 - 58) segment can be activated in the fragments (41 - 61) and (46 - 61) by 1 per cent sodium dodecylsulfate, although the spectrum is not indicative of a classical alpha-helix. However, the conformation in the (51 to 58) segment should also be non-random in native C-peptide, since cleavage of the (46 - 61) fragment into the subfragments (46 - 52) and (53 - 61) causes considerable spectral effects. Cleavage of the other potentially helical region (38 to 44) between residues 40 and 41, on the other hand, is without spectral consequences. Therefore, this segment is unlikely to be helical in native C-peptide. In the coherent C-peptide, the helix formation which can be induced by sodium dodecylsulfate in the C-terminal part is apparently inhibited by interaction with the N-terminal half of the molecule. This interaction implies that the chain is folded back on itself, which is consistent with a high probability of bets turn formation in the segment (45 to 50). The CD spectra of the fragments (41 - 52) and (46 - 52), in which the beta turn could occur, are characterized by positive ellipticity about 213 nm. The correlation of the beta turn with this type of spectrum as well as its definite location are discussed, but cannot be proved solely on CD spectroscopic grounds.
More Related Videos
10:26Biotinylated Cell-penetrating Peptides to Study Intracellular Protein-protein Interactions
Published on: December 20, 2017
06:50Computational Prediction of Amino Acid Preferences of Potentially Multispecific Peptide-Binding Domains Involved in Protein-Protein Interactions
Published on: January 26, 2024
Related Concept Videos
Protein and Protein Structure
A protein's shape is critical to its function. For example, an enzyme can...
Cell Specific Gene Expression
Insulin Secretory Vesicles
Protein Folding
Protein Structure Is Critical to Its Biological Function
Proteins perform a wide range of biological functions such as catalyzing chemical reactions, providing...
Insulin: Biosynthesis, Chemistry, and Preparation
Damage or functional impairment of β-cells inhibits insulin production, leading to diabetes. Diabetes treatment primarily uses...
Production of Pharmaceuticals