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Structural analysis of bovine pancreatic thread protein
L Cai1, W R Harris, D R Marshak
1W. Alton Jones Cell Science Center, Inc., Lake Placid, New York 12946.
Journal of Protein Chemistry
|October 1, 1990
Summary
Pancreatic thread protein (PTP) is composed of two disulfide-bonded polypeptide chains, A and B, with determined sequences and molecular weights. This structural elucidation provides a foundation for understanding PTP
Area of Science:
- Biochemistry
- Molecular Biology
- Protein Chemistry
Background:
- Pancreatic thread protein (PTP) exhibits pH-dependent globule-fibril transformation.
- Purified bovine PTP consists of two carbohydrate-free polypeptide chains.
Purpose of the Study:
- To confirm the polypeptide composition and determine the amino acid sequences of bovine PTP.
- To elucidate the structural basis of PTP's double helical formation and pH-dependent transformations.
Main Methods:
- Plasma desorption mass spectrometry for molecular weight determination.
- Amino acid sequence analysis using gas-phase Edman degradation and peptide cleavage.
- Analysis of bovine PTP cDNA structure.
Main Results:
- Bovine PTP comprises two disulfide-bonded polypeptides: chain A (101 residues, 11,073 Da) and chain B (35 residues, 3970 Da).
- The intact protein's molecular weight (15,036 Da) closely matches the calculated sequence-based weight.
- The two chains originate from a single precursor polypeptide.
- Structural homology was found with human and rat pancreatic proteins and carbohydrate recognition domains.
Conclusions:
- The complete amino acid sequences of the A and B chains of bovine PTP have been determined.
- These findings establish a solid molecular foundation for future studies on PTP's structure-function relationships.
- PTP's potential roles in pancreatic secretion and neurological conditions warrant further investigation.