7NG5

P1c-state of wild type human mitochondrial LONP1 protease with bound substrate protein in presence of ATP/ADP mix

Summary for 7NG5

• Entry DOI: 10.2210/pdb7ng5/pdb
• Related: 7NG4 7NGC 7NGF 7NGL 7NGP 7NGQ
• EMDB information: 12307 12308 12312 12313 12315 12316 12317
• Descriptor: Lon protease homolog, mitochondrial, Substrate protein chain:G, ADENOSINE-5'-TRIPHOSPHATE, ... (5 entities in total)
• Functional Keywords: human mitochondrial aaa+ protease, motor protein
• Biological source: Homo sapiens (Human); More
• Total number of polymer chains: 7
• Total formula weight: 585515.96

Authors

Mohammed, I.,Schmitz, K.A.,Schenck, N.,Maier, T.,Abrahams, J.P. (deposition date: 2021-02-08, release date: 2021-02-24, Last modification date: 2024-07-10)

Primary citation

Mohammed, I.,Schmitz, K.A.,Schenck, N.,Balasopoulos, D.,Topitsch, A.,Maier, T.,Abrahams, J.P.
Catalytic cycling of human mitochondrial Lon protease.
Structure, 30:1254-1268.e7, 2022

PubMed Abstract: 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.

PubMed: 35870450
DOI: 10.1016/j.str.2022.06.006

Experimental method

ELECTRON MICROSCOPY (3.8 Å)