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Fusion of Ssm6a with a protein scaffold retains selectivity on Na V 1.7 and improves its therapeutic potential against chronic pain
Author(s) -
Wang Chuan,
Shan Bin,
Wang Qiong,
Xu Qunyuan,
Zhang Hailin,
Lei Huimeng
Publication year - 2017
Publication title -
chemical biology and drug design
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.59
H-Index - 77
eISSN - 1747-0285
pISSN - 1747-0277
DOI - 10.1111/cbdd.12915
Subject(s) - venom , fusion protein , peptide , mutagenesis , chemistry , sodium channel , scaffold , potency , selectivity , disulfide bond , protein engineering , biochemistry , computational biology , in vitro , biology , recombinant dna , gene , medicine , sodium , mutant , biomedical engineering , catalysis , enzyme , organic chemistry
Voltage‐gated sodium channel Na V 1.7 serves as an attractive target for chronic pain treatment. Several venom peptides were found to selectively inhibit Na V 1.7 but with intrinsic problems. Among them, Ssm6a, a recently discovered centipede venom peptide, shows the greatest selectivity against Na V 1.7, but dissociates from the target too fast and loses bioactivity in synthetic forms. As a disulfide‐rich venom peptide, it is difficult to optimize Ssm6a by artificial mutagenesis and produce the peptide with common industrial manufacturing methods. Here, we developed a novel protein scaffold fusion strategy to address these concerns. Instead of directly mutating Ssm6a, we genetically fused Ssm6a with a protein scaffold engineered from human muscle fatty acid‐binding protein. The resultant fusion protein, SP‐TOX, maintained the selectivity and potency of Ssm6a upon Na V 1.7 but dissociated from target at least 10 times more slowly. SP‐TOX dramatically reduced inflammatory pain in a rat model through DRG‐targeted delivery. Importantly, SP‐TOX can be expressed cytosolically in Escherichia coli and purified in a cost‐effective way. In summary, our study provided the first example of cytosolically expressed fusion protein with high potency and selectivity on Na V 1.7. Our protein scaffold fusion approach may have its broad application in optimizing disulfide‐rich venom peptides for therapeutic usage.