科研之友
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摘要
The Ca2+-sensitive cardiac troponin (cTn) is a hetero-trimer complex consisting of three subunits cTnC, cTnI, and cTnT, which has been recognized as an important biomarker and a potential target of cardiovascular diseases. Previously, several small-molecule agents such as levosimendan and pimobendan have been successfully developed to target this protein for the treatment of heart failure. Here, instead of small-molecule chemical drugs, we purposed rational derivation of self-inhibitory peptides as potential biologic disruptors of cTnC-cTnI interaction from the interaction complex interface. In the procedure, the crystal structure of cTn trimer was examined in detail using bioinformatics approach, from which a peptide-mediated interaction between the N-terminal domain of cTnC and the switch region of cTnI was identified. The switch is a 19-mer peptide segment Swt that contains a structured helical core capped by a short N-terminal tripeptide and a disordered C-terminal tail. Structural and energetic analysis revealed that the Swt peptide binds independently to cTnC N-terminal domain, which can be stripped from the intact cTnI subunit to interact effectively with cTnC. Further investigations found that truncation of two N-terminal residues and five C-terminal residues of the full-length Swt peptide, resulting in a shortened version namely Swt-Delta N2 Delta C5 peptide, would not cause substantial loss in its binding potency to cTnC. The computational finding was then confirmed by using fluorescence-based affinity assays; the Swt and Swt-Delta N2 Delta C5 peptides was experimentally measured to have a moderately high affinity to the recombinant protein of human cTnC N-terminal domain with K (d) values at micromolar level. The Swt and Swt-Delta N2 Delta C5 are considered as inhibitory peptides that can be further optimized and modified to obtain high-affinity disruptors of cTnI-cTnC interaction.
- 出版日期2017-9
- 单位上海交通大学; 上海市闵行区中心医院
