ジャーナル: Sci Adv / 年: 2021 タイトル: Processive cleavage of substrate at individual proteolytic active sites of the Lon protease complex. 著者: Shanshan Li / Kan-Yen Hsieh / Chiao-I Kuo / Shih-Chieh Su / Kai-Fa Huang / Kaiming Zhang / Chung-I Chang / 要旨: The Lon protease is the prototype of a family of proteolytic machines with adenosine triphosphatase modules built into a substrate degradation chamber. Lon is known to degrade protein substrates in a ...The Lon protease is the prototype of a family of proteolytic machines with adenosine triphosphatase modules built into a substrate degradation chamber. Lon is known to degrade protein substrates in a processive fashion, cutting a protein chain processively into small peptides before commencing cleavages of another protein chain. Here, we present structural and biochemical evidence demonstrating that processive substrate degradation occurs at each of the six proteolytic active sites of Lon, which forms a deep groove that partially encloses the substrate polypeptide chain by accommodating only the unprimed residues and permits processive cleavage in the C-to-N direction. We identify a universally conserved acidic residue at the exit side of the binding groove indispensable for the proteolytic activity. This noncatalytic residue likely promotes processive proteolysis by carboxyl-carboxylate interactions with cleaved intermediates. Together, these results uncover a previously unrecognized mechanism for processive substrate degradation by the Lon protease.
解像度: 2.12→29.93 Å / Cor.coef. Fo:Fc: 0.95 / Cor.coef. Fo:Fc free: 0.932 / SU B: 3.498 / SU ML: 0.093 / 交差検証法: THROUGHOUT / σ(F): 0 / ESU R: 0.146 / ESU R Free: 0.143 / 立体化学のターゲット値: MAXIMUM LIKELIHOOD 詳細: HYDROGENS HAVE BEEN ADDED IN THE RIDING POSITIONS U VALUES : REFINED INDIVIDUALLY
Rfactor
反射数
%反射
Selection details
Rfree
0.22
2934
5.1 %
RANDOM
Rwork
0.1805
-
-
-
obs
0.1825
55096
99.63 %
-
溶媒の処理
イオンプローブ半径: 0.8 Å / 減衰半径: 0.8 Å / VDWプローブ半径: 1.2 Å / 溶媒モデル: MASK