Affinity capture of [Arg8]vasopressin-receptor complex using immobilized antisense peptide

Area of Science:

• Biochemistry
• Molecular Biology
• Pharmacology

Background:

• Solubilized noncovalent complexes of [Arg8]-vasopressin (AVP) with receptor proteins were studied.
• Rat liver membranes were used as the source of AVP receptors.
• Antisense (AS) peptide, derived from the AVP precursor, was hypothesized to bind AVP-receptor complexes.

Purpose of the Study:

• To isolate and characterize [Arg8]-vasopressin (AVP) receptor complexes from rat liver membranes.
• To test the hypothesis that immobilized AS peptide can selectively bind to AVP-receptor complexes.
• To investigate the potential of AS peptide affinity chromatography for studying peptide-receptor interactions.

Main Methods:

• Preparation of silica-immobilized AS peptide targeting the N-terminal region of the AVP precursor.
• Affinity chromatography using the AS peptide column to capture solubilized [3H]AVP-receptor complexes.
• Chemical crosslinking, SDS/PAGE, and scintillation counting to detect and analyze bound radiolabeled proteins.

Main Results:

• The AS peptide column successfully isolated [3H]AVP-receptor complexes from rat liver membrane fractions.
• Two major radiolabeled bands at 31 and 38 kDa were detected, corresponding to AVP-receptor complexes.
• A 15 kDa radiolabeled protein fragment was identified, potentially an active receptor component.

Conclusions:

• Immobilized AS peptides are effective for isolating peptide-receptor complexes.
• The AS peptide affinity column specifically captured AVP-receptor complexes, confirmed by competition assays.
• The identified protein bands represent AVP-receptor complexes and a potential active fragment, validating the method for broader applications.