1T0C

Solution Structure of Human Proinsulin C-Peptide

Summary for 1T0C

• Entry DOI: 10.2210/pdb1t0c/pdb
• Descriptor: Insulin (1 entity in total)
• Functional Keywords: type i beta-turn, bend, type iii' beta-turn, hormone-growth factor complex, hormone/growth factor
• Biological source: Homo sapiens (human)
• Cellular location: Secreted: P01308
• Total number of polymer chains: 1
• Total formula weight: 3020.26

Authors

Munte, C.E.,Vilela, L.,Kalbitzer, H.-R.,Garratt, R.C. (deposition date: 2004-04-08, release date: 2005-08-16, Last modification date: 2024-05-22)

Primary citation

Munte, C.E.,Vilela, L.,Kalbitzer, H.-R.,Garratt, R.C.
Solution structure of human proinsulin C-peptide
Febs J., 272:4284-4293, 2005

PubMed Abstract: The C-peptide of proinsulin is important for the biosynthesis of insulin, but has been considered for a long time to be biologically inert. Recent studies in diabetic patients have stimulated a new debate about its possible regulatory role, suggesting that it is a hormonally active peptide. We describe structural studies of the C-peptide using 2D NMR spectroscopy. In aqueous solution, the NOE patterns and chemical shifts indicate that the ensemble is a nonrandom structure and contains substructures with defined local conformations. These are more clearly visible in 50% H2O/50% 2,2,2-trifluoroethanol. The N-terminal region (residues 2-5) forms a type I beta-turn, whereas the C-terminal region (residues 27-31) presents the most well-defined structure of the whole molecule including a type III'beta-turn. The C-terminal pentapeptide (EGSLQ) has been suggested to be responsible for chiral interactions with an as yet uncharacterized, probably a G-protein-coupled, receptor. The three central regions of the molecule (residues 9-12, 15-18 and 22-25) show tendencies to form beta-bends. We propose that the structure described here for the C-terminal pentapeptide is consistent with the previously postulated CA knuckle, believed to represent the active site of the C-peptide of human proinsulin.

PubMed: 16098208
DOI: 10.1111/j.1742-4658.2005.04843.x

Experimental method

SOLUTION NMR