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Effects of Cyclization on Activity and Stability of α-Conotoxin TxIB

Xincan Li1, Shuai Wang1, Xiaopeng Zhu1

  • 1Key Laboratory of Tropical Biological Resources of Ministry of Education, Key Laboratory for Marine Drugs of Haikou, School of Life and Pharmaceutical Sciences, Hainan University, Haikou 570228, China.

Marine Drugs
|April 3, 2020
PubMed

Insights

Cyclizing alpha-conotoxin TxIB enhanced its stability in human serum without affecting its ability to block alpha6/alpha3beta2beta3 nicotinic acetylcholine receptors (nAChRs). This modification improves TxIB

Area of Science:

  • Neuroscience
  • Pharmacology
  • Biochemistry

Background:

  • Alpha-conotoxin TxIB is a selective blocker of alpha6/alpha3beta2beta3 nicotinic acetylcholine receptors (nAChRs).
  • Peptide-based drugs like TxIB often face challenges with stability, half-life, and bioavailability.
  • Improved stability is crucial for developing TxIB as a research probe for addiction and neurological disorders.

Purpose of the Study:

  • To enhance the stability of alpha-conotoxin TxIB through backbone cyclization.
  • To evaluate the impact of cyclization on the inhibitory activity of TxIB against alpha6/alpha3beta2beta3 nAChRs.
  • To assess the stability of cyclic TxIB analogues in human serum.

Main Methods:

  • Synthesis of four cyclic TxIB (cTxIB) analogues using different linker lengths.
  • Measurement of inhibitory activity of cTxIB analogues against alpha6/alpha3beta2beta3 nAChRs.
  • Assessment of cTxIB stability in human serum over time.

Main Results:

  • All synthesized cTxIB analogues retained similar inhibitory activity compared to wild-type TxIB.
  • Backbone cyclization did not significantly alter the pharmacological activity of TxIB.
  • Cyclization using a seven-residue linker markedly improved TxIB's stability in human serum.

Conclusions:

  • Backbone cyclization is a viable strategy to enhance the stability of alpha-conotoxin TxIB.
  • Cyclization preserves the specific activity of TxIB against alpha6/alpha3beta2beta3 nAChRs.
  • Stabilized TxIB analogues hold promise for future applications in neuroscience research and therapeutics.
Keywords:
activitycyclizationstabilityα-conotoxin TxIBα6/α3β2β3 nAChRs

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