7NG5 image
Entry Detail
PDB ID:
7NG5
EMDB ID:
Keywords:
Title:
P1c-state of wild type human mitochondrial LONP1 protease with bound substrate protein in presence of ATP/ADP mix
Biological Source:
Source Organism:
PDB Version:
Deposition Date:
2021-02-08
Release Date:
2021-02-24
Method Details:
Experimental Method:
Resolution:
3.80 Å
Aggregation State:
PARTICLE
Reconstruction Method:
SINGLE PARTICLE
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Lon protease homolog, mitochondrial
Chain IDs:A, B, C, D, E, F
Chain Length:853
Number of Molecules:6
Biological Source:Homo sapiens
Polymer Type:polypeptide(L)
Description:Substrate protein chain:G
Chain IDs:G
Chain Length:55
Number of Molecules:1
Biological Source:Homo sapiens
Primary Citation
Catalytic cycling of human mitochondrial Lon protease.
Structure 30 1254 1268.e7 (2022)
PMID: 35870450 DOI: 10.1016/j.str.2022.06.006

Abstact

The mitochondrial Lon protease (LonP1) regulates mitochondrial health by removing redundant proteins from the mitochondrial matrix. We determined LonP1 in eight nucleotide-dependent conformational states by cryoelectron microscopy (cryo-EM). The flexible assembly of N-terminal domains had 3-fold symmetry, and its orientation depended on the conformational state. We show that a conserved structural motif around T803 with a high similarity to the trypsin catalytic triad is essential for proteolysis. We show that LonP1 is not regulated by redox potential, despite the presence of two conserved cysteines at disulfide-bonding distance in its unfoldase core. Our data indicate how sequential ATP hydrolysis controls substrate protein translocation in a 6-fold binding change mechanism. Substrate protein translocation, rather than ATP hydrolysis, is a rate-limiting step, suggesting that LonP1 is a Brownian ratchet with ATP hydrolysis preventing translocation reversal. 3-fold rocking motions of the flexible N-domain assembly may assist thermal unfolding of the substrate protein.

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