Crystal Structure of Mycobacterium tuberculosis Zinc-dependent Metalloprotease-1 (Zmp1), a Metalloprotease Involved in Pathogenicity

Davide M Ferraris,Diego Sbardella,Agnese Petrera,Stefano Marini,Beat Amstutz,Massimo Coletta,Peter Sander,Menico Rizzi

doi:10.1074/jbc.m111.271809

Abstract

Mycobacterium tuberculosis, the causative agent of tuberculosis, parasitizes host macrophages. The resistance of the tubercle bacilli to the macrophage hostile environment relates to their ability to impair phagosome maturation and its fusion with the lysosome, thus preventing the formation of the phago-lysosome and eventually arresting the process of phagocytosis. The M. tuberculosis zinc-dependent metalloprotease Zmp1 has been proposed to play a key role in the process of phagosome maturation inhibition and emerged as an important player in pathogenesis. Here, we report the crystal structure of wild-type Zmp1 at 2.6 Å resolution in complex with the generic zinc metalloprotease inhibitor phosphoramidon, which we demonstrated to inhibit the enzyme potently. Our data represent the first structural characterization of a bacterial member of the zinc-dependent M13 endopeptidase family and revealed a significant degree of conservation with eukaryotic enzymes. However, structural comparison of the Zmp1-phosphoramidon complex with homologous human proteins neprilysin and endothelin-converting enzyme-1 revealed unique features of the Zmp1 active site to be exploited for the rational design of specific inhibitors that may prove useful as a pharmacological tool for better understanding Zmp1 biological function.

Highlights

Mycobacterium tuberculosis, the causative agent of tuberculosis, parasitizes host macrophages
The M. tuberculosis zinc-dependent metalloprotease Zmp1 has been proposed to play a key role in the process of phagosome maturation inhibition and emerged as an important player in pathogenesis
Inhaled M. tuberculosis bacteria are phagocytosed by resident macrophages in the lungs, i.e. the alveolar macrophages, but not efficiently cleared [4]

Summary

Crystal Structure of Mycobacterium tuberculosis

Zinc-dependent Metalloprotease-1 (Zmp1), a Metalloprotease Involved in Pathogenicity*□S. The M. tuberculosis zinc-dependent metalloprotease Zmp has been proposed to play a key role in the process of phagosome maturation inhibition and emerged as an important player in pathogenesis. Some pathogens, among them M. tuberculosis, have evolved the ability to preclude the macrophages killing by inhibiting the phagosome maturation process [7, 8] This step is critical for the progression of the infection because it compromises bacterial clearance [9] and antigen processing [10, 11]. Structure-Inhibition of M. tuberculosis Zinc-dependent Zmp consequent phagosome maturation They furnish evidence that suppression of the zmp gene reestablished the activation of caspase-1, the production of IL-1␤, and the full maturation of the phagosome into phago-lysosome, leading to the clearance of the pathogen. The authors proposed that the blocking of the phagosome maturation process is due to the inhibition of the inflammasome by the secreted M. tuberculosis protein Zmp (Zn-dependent metalloprotease-1). Subtle differences are present in the catalytic site of Zmp that could be exploited for the design of specific inhibitors against the mycobacterial enzyme

EXPERIMENTAL PROCEDURES

RESULTS

DISCUSSION