Alanine scan of the opioid peptide dynorphin B amide

作者：Joshi Anand A; Murray Thomas F; Aldrich Jane V^*

来源：Biopolymers, 2017, 108(5): e23026.

DOI：10.1002/bip.23026

• alanine scan
• C-terminal basic residues
• dynorphin B
• kappa opioid receptor
• structure-activity relationships

To date structure-activity relationship (SAR) studies of the dynorphins (Dyn), endogenous peptides for kappa opioid receptors (KOR), have focused almost exclusively on Dyn A with minimal studies on Dyn B. While both Dyn A and Dyn B have identical N-terminal sequences, their C-terminal sequences differ, which could result in differences in pharmacological activity. We performed an alanine scan of the non-glycine residues up through residue 11 of Dyn B amide to explore the roles of these side chains in the activity of Dyn B. The analogs were synthesized by fluorenylme-thyloxycarbonyl (Fmoc)-based solid phase peptide synthesis and evaluated for their opioid receptor affinities and opioid potency and efficacy at KOR. Similar to Dyn A the N-terminal Tyr(1) and Phe(4) residues of Dyn B amide are critical for opioid receptor affinity and KOR agonist potency. The basic residues Arg(6) and Arg(7) contribute to the KOR affinity and agonist potency of Dyn B amide, while Lys(10) contributes to the opioid receptor affinity, but not KOR agonist potency, of this peptide. Comparison to the Ala analogs of Dyn A (1-13) suggests that the basic residues in the C-terminus of both peptides contribute to KOR binding, but differences in their relative positions may contribute to the different pharmacological profiles of Dyn A and Dyn B. The other unique C-terminal residues in Dyn B amide also appear to influence the relative affinity of this peptide for KOR versus mu and delta opioid receptors. This SAR information may be applied in the design of new Dyn B analogs that could be useful pharmacological tools.

• 出版日期2017-9