endopeptidase La / ATP-dependent peptidase activity / protein quality control for misfolded or incompletely synthesized proteins / cellular response to heat / sequence-specific DNA binding / serine-type endopeptidase activity / ATP hydrolysis activity / ATP binding / metal ion binding / identical protein binding / cytoplasm 類似検索 - 分子機能
ジャーナル: Structure / 年: 2016 タイトル: Structural Basis for the Magnesium-Dependent Activation and Hexamerization of the Lon AAA+ Protease. 著者: Shih-Chieh Su / Chien-Chu Lin / Hui-Chung Tai / Mu-Yueh Chang / Meng-Ru Ho / C Satheesan Babu / Jiahn-Haur Liao / Shih-Hsiung Wu / Yuan-Chih Chang / Carmay Lim / Chung-I Chang / 要旨: The Lon AAA+ protease (LonA) plays important roles in protein homeostasis and regulation of diverse biological processes. LonA behaves as a homomeric hexamer in the presence of magnesium (Mg(2+)) and ...The Lon AAA+ protease (LonA) plays important roles in protein homeostasis and regulation of diverse biological processes. LonA behaves as a homomeric hexamer in the presence of magnesium (Mg(2+)) and performs ATP-dependent proteolysis. However, it is also found that LonA can carry out Mg(2+)-dependent degradation of unfolded protein substrate in an ATP-independent manner. Here we show that in the presence of Mg(2+) LonA forms a non-secluded hexameric barrel with prominent openings, which explains why Mg(2+)-activated LonA can operate as a diffusion-based chambered protease to degrade unstructured protein and peptide substrates efficiently in the absence of ATP. A 1.85 Å crystal structure of Mg(2+)-activated protease domain reveals Mg(2+)-dependent remodeling of a substrate-binding loop and a potential metal-binding site near the Ser-Lys catalytic dyad, supported by biophysical binding assays and molecular dynamics simulations. Together, these findings reveal the specific roles of Mg(2+) in the molecular assembly and activation of LonA.
解像度: 3.03→20 Å / Cor.coef. Fo:Fc: 0.916 / Cor.coef. Fo:Fc free: 0.871 / SU B: 23.78 / SU ML: 0.415 / 交差検証法: THROUGHOUT / ESU R Free: 0.542 / 立体化学のターゲット値: MAXIMUM LIKELIHOOD / 詳細: HYDROGENS HAVE BEEN ADDED IN THE RIDING POSITIONS
Rfactor
反射数
%反射
Selection details
Rfree
0.279
3798
5.1 %
RANDOM
Rwork
0.227
-
-
-
obs
0.23
70806
90.5 %
-
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