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MHJ_0125 is an M42 glutamyl aminopeptidase that moonlights as a multifunctional adhesin on the surface of Mycoplasma hyopneumoniae

Authors :
Mark W. Robinson
Kyle A. Buchtmann
Cheryl Jenkins
Jessica L. Tacchi
Benjamin B. A. Raymond
Joyce To
Piklu Roy Chowdhury
Lauren K. Woolley
Maurizio Labbate
Lynne Turnbull
Cynthia B. Whitchurch
Matthew P. Padula
Steven P. Djordjevic
Source :
Open Biology, Vol 3, Iss 4 (2013)
Publication Year :
2013
Publisher :
The Royal Society, 2013.

Abstract

Bacterial aminopeptidases play important roles in pathogenesis by providing a source of amino acids from exogenous proteins, destroying host immunological effector peptides and executing posttranslational modification of bacterial and host proteins. We show that MHJ_0125 from the swine respiratory pathogen Mycoplasma hyopneumoniae represents a new member of the M42 class of bacterial aminopeptidases. Despite lacking a recognizable signal sequence, MHJ_0125 is detectable on the cell surface by fluorescence microscopy and LC-MS/MS of (i) biotinylated surface proteins captured by avidin chromatography and (ii) peptides released by mild trypsin shaving. Furthermore, surface-associated glutamyl aminopeptidase activity was detected by incubation of live M. hyopneumoniae cells with the diagnostic substrate H-Glu-AMC. MHJ_0125 moonlights as a multifunctional adhesin, binding to both heparin and plasminogen. Native proteomics and comparative modelling studies suggest MHJ_0125 forms a dodecameric, homopolymeric structure and provide insight into the positions of key residues that are predicted to interact with heparin and plasminogen. MHJ_0125 is the first aminopeptidase shown to both bind plasminogen and facilitate its activation by tissue plasminogen activator. Plasmin cleaves host extracellular matrix proteins and activates matrix metalloproteases, generating peptide substrates for MHJ_0125 and a source of amino acids for growth of M. hyopneumoniae. This unique interaction represents a new paradigm in microbial pathogenesis.

Details

Language :
English
ISSN :
20462441
Volume :
3
Issue :
4
Database :
Directory of Open Access Journals
Journal :
Open Biology
Publication Type :
Academic Journal
Accession number :
edsdoj.1ee189f5a15245ab8126bc34fc5f1c0e
Document Type :
article
Full Text :
https://doi.org/10.1098/rsob.130017