Characterization of anti-inflammatory effect of soybean septapeptide and its molecular mechanism

Activation of nuclear factor kappa B ($NF{\kappa}B$) leads to the inflammatory process. During this $NF{\kappa}B$-dependent inflammation process, inducible nitric oxide synthase (iNOS) are expressed in the inflammatory cells. Our previous data indicated that a specific septapeptide (GVAWWMY) from the soybean extract fermented by Bacillus licheniformis B1 inhibited iNOS mRNA expression and NO production in cultured macrophage cells. Our further experiments revealed that treatment of same septapeptide resulted in inhibition of LPS-induced $NF{\kappa}B$ activation by reversing degradation of $I{\kappa}B{\alpha}$, an inhibitory protein for $NF{\kappa}B$. The molecular docking indicated that the septapeptide binds to $I{\kappa}B$ kinase ${\beta}$ ($IKK{\beta}$), and thus it can inhibit phosphorylation of $I{\kappa}B{\alpha}$. Supporting this, the binding site for the septapeptide has the highest affinity (-8.7 kcal/mol) and the site was located at the kinase domain (KD) of $IKK{\beta}$, which can significantly affect the kinase activity of $IKK{\beta}$.

대두 septapeptide의 항염 효과 및 분자 기작 규명

Nuclear factor kappa B ($NF{\kappa}B$)의 활성화는 염증을 일으킨다. 이 때, inducible nitric oxide synthase (iNOS)가 발현된다. 우리 선행 연구에 의하면 Bacillus licheniformis B1에 의해 제조된 발효대두에 있는 septapeptide (GVAWWMY)가 대식세포에서 iNOS mRNA 발현과 NO 생산을 억제하였다. 본 연구에서 septapeptide의 처리가 $I{\kappa}B{\alpha}$ ($NF{\kappa}B$ 억제 단백질)의 분해를 억제하여 LPS에 의해 유도되는 $NF{\kappa}B$의 활성화를 억제함을 확인했다. 분자 docking에 의해 septapeptide가 ${\kappa}B$ kinase ${\beta}$ ($IKK{\beta}$)에 부착하여 $I{\kappa}B{\alpha}$의 인산화를 방해할 가능성이 있다. Septapeptide는 높은 친화도로(-8.7 kcal/Mol) $IKK{\beta}$의 kinase domain에 부착해서 kinase 활성에 크게 영향을 미칠 수 있다.