Essential function of the N-termini tails of the proteasome for the gating mechanism revealed by molecular dynamics simulations

分子動力学シミュレーションを用いたプロテアソームN末端のゲート機構に対する機能発現解析

石田 恒

Ishida, Hisashi

Proteasome is involved in the degradation of proteins. Proteasome activators bind to the proteasome core particle (CP) and facilitate opening a gate of the CP, where Tyr8 and Asp9 in the N-termini tails of the CP form the ordered open gate. Four different molecular dynamics simulations were carried out: ordered- and Tyr8Gly/Asp9Gly disordered-gate models of the CP complexed with an ATP-independent PA26 and ordered- and disordered-gate models of the CP complexed with an ATP-dependent PAN-like activator. In the ordered-gate models, the substrate in the activator was more stable than that in the CP. In the disordered-gate models, the substrate in the activator was more destabilized than in the ordered-gate models. Thus, it was concluded that the dynamics of the N-termini tails entropically play a key role in the translocation of the substrate.