Cryo-EM structure of substrate-free E. coli Lon protease provides insights into the dynamics of Lon machinery

Author:

Botos, Istvan

Lountos,George

Wu,Weimin

Cherry,Scott

Ghirlando, Rodolfo

Kudzhaev, Arsen M

Rotanova, Tatyana V

de Val, Natalia

Tropea,Joseph

Gustchina,Alla

Wlodawer,Alexander
Author Address

Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA., Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD 21702, USA., Basic Science Program, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA., Center for Molecular Microscopy, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA., Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia., Electron Microscopy Laboratory, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA.,

Abstract:

Energy-dependent Lon proteases play a key role in cellular regulation by degrading short-lived regulatory proteins and misfolded proteins in the cell. The structure of the catalytically inactive S679A mutant of Escherichia coli LonA protease (EcLon) has been determined by cryo-EM at the resolution of 3.5 160; 197;. EcLonA without a bound substrate adopts a hexameric open-spiral quaternary structure that might represent the resting state of the enzyme. Upon interaction with substrate the open-spiral hexamer undergoes a major conformational change resulting in a compact, closed-circle hexamer as in the recent structure of a complex of Yersinia pestis LonA with a protein substrate. This major change is accomplished by the rigid-body rearrangement of the individual domains within the protomers of the complex around the hinge points in the interdomain linkers. Comparison of substrate-free and substrate-bound Lon structures allows to mark the location of putative pivotal points involved in such conformational changes.

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