title: MHJ_0125 is an M42 glutamyl aminopeptidase that moonlights as a multifunctional adhesin on the surface of Mycoplasma hyopneumoniae.
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.
authors.affiliation: Ithree institute, University of Technology, Sydney PO Box 123, Broadway, New South Wales 2007, Australia.
authors.forename: Mark W
authors.initials: MW
authors.lastname: Robinson
authors.forename: Kyle A
authors.initials: KA
authors.lastname: Buchtmann
authors.forename: Cheryl
authors.initials: C
authors.lastname: Jenkins
authors.forename: Jessica L
authors.initials: JL
authors.lastname: Tacchi
authors.forename: Benjamin B A
authors.initials: BB
authors.lastname: Raymond
authors.forename: Joyce
authors.initials: J
authors.lastname: To
authors.forename: Piklu
authors.initials: P
authors.lastname: Roy Chowdhury
authors.forename: Lauren K
authors.initials: LK
authors.lastname: Woolley
authors.forename: Maurizio
authors.initials: M
authors.lastname: Labbate
authors.forename: Lynne
authors.initials: L
authors.lastname: Turnbull
authors.forename: Cynthia B
authors.initials: CB
authors.lastname: Whitchurch
authors.forename: Matthew P
authors.initials: MP
authors.lastname: Padula
authors.forename: Steven P
authors.initials: SP
authors.lastname: Djordjevic
mesh_terms: D018829:Adhesins, Bacterial / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D043384:Glutamyl Aminopeptidase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006493:Heparin / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D045705:Mycoplasma hyopneumoniae / Q000145:classification / Q000201:enzymology* / Q000378:metabolism; D010802:Phylogeny; D010958:Plasminogen / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D040901:Proteomics; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D016415:Sequence Alignment; D013552:Swine / Q000382:microbiology
chemical_list: D018829:Adhesins, Bacterial; D001426:Bacterial Proteins; D011994:Recombinant Proteins; D010958:Plasminogen; D006493:Heparin; D043384:Glutamyl Aminopeptidase