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Archaea
Volume 2016 (2016), Article ID 5759765, 7 pages
http://dx.doi.org/10.1155/2016/5759765
Research Article

Characterization of the ATP-Dependent Lon-Like Protease in Methanobrevibacter smithii

1Department of Gastroenterology, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou 325027, China
2Plant Protection College, Shenyang Agricultural University, Shenyang 110161, China
3College of Life Science, Dalian Nationalities University, Dalian 116600, China

Received 1 December 2015; Revised 22 February 2016; Accepted 28 March 2016

Academic Editor: Stefan Spring

Copyright © 2016 Jihua Pei et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The Lon protease is highly evolutionarily conserved. However, little is known about Lon in the context of gut microbial communities. A gene encoding a Lon-like protease (Lon-like-Ms) was identified and characterized from Methanobrevibacter smithii, the predominant archaeon in the human gut ecosystem. Phylogenetic and sequence analyses showed that Lon-like-Ms and its homologs are newly identified members of the Lon family. A recombinant form of the enzyme was purified by affinity chromatography, and its catalytic properties were examined. Recombinant Lon-like-Ms exhibited ATPase activity and cleavage activity toward fluorogenic peptides and casein. The peptidase activity of Lon-like-Ms relied strictly on Mg2+ (or other divalent cations) and ATP. These results highlight a new type of Lon-like protease that differs from its bacterial counterpart.