title: P40 and P90 from Mpn142 are Targets of Multiple Processing Events on the Surface ofMycoplasma pneumoniae.
abstract: Mycoplasma pneumoniaeis a significant cause of community acquired pneumonia globally. Despite having a genome less than 1 Mb in size,M. pneumoniaepresents a structurally sophisticated attachment organelle that (i) provides cell polarity, (ii) directs adherence to receptors presented on respiratory epithelium, and (iii) plays a major role in cell motility. The major adhesins, P1 (Mpn141) and P30 (Mpn453), are localised to the tip of the attachment organelle by the surface accessible cleavage fragments P90 and P40 derived from Mpn142. Two events play a defining role in the formation of P90 and P40; removal of a leader peptide at position 26 (23SLA↓NTY28) during secretion to the cell surface and cleavage at amino acid 455 (452GPL↓RAG457) generating P40 and P90. Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS) analysis of tryptic peptides generated by digesting size-fractionated cell lysates ofM. pneumoniaeidentified 15 cleavage fragments of Mpn142 ranging in mass from 9-84 kDa. Further evidence for the existence of cleavage fragments of Mpn142 was generated by mapping tryptic peptides to proteins recovered from size fractionated eluents from affinity columns loaded with heparin, fibronectin, fetuin, actin, plasminogen and A549 surface proteins as bait. To define the sites of cleavage in Mpn142, neo-N-termini in cell lysates ofM. pneumoniaewere dimethyl-labelled and characterised by LC-MS/MS. Our data suggests that Mpn142 is cleaved to generate adhesins that are auxiliary to P1 and P30.
authors.affiliation: ithree institute, University of Technology Sydney, P.O. Box 123 Broadway, Ultimo, NSW 2007, Australia. michael.widjaja@student.uts.edu.au.
authors.forename: Michael
authors.initials: M
authors.lastname: Widjaja
authors.affiliation: ithree institute, University of Technology Sydney, P.O. Box 123 Broadway, Ultimo, NSW 2007, Australia. iain.j.berry@student.uts.edu.au.
authors.forename: Iain J
authors.initials: IJ
authors.lastname: Berry
authors.affiliation: ithree institute, University of Technology Sydney, P.O. Box 123 Broadway, Ultimo, NSW 2007, Australia. elsa.pont@etudiant.univ-lille1.fr.
authors.forename: Elsa J
authors.initials: EJ
authors.lastname: Pont
authors.affiliation: Proteomics Core Facility, University of Technology Sydney, Cnr Harris and Thomas St, Ultimo, NSW 2007, Australia. matthew.padula@uts.edu.au.
authors.forename: Matthew P
authors.initials: MP
authors.lastname: Padula
authors.affiliation: ithree institute, University of Technology Sydney, P.O. Box 123 Broadway, Ultimo, NSW 2007, Australia. steven.djordjevic@uts.edu.au.|Proteomics Core Facility, University of Technology Sydney, Cnr Harris and Thomas St, Ultimo, NSW 2007, Australia. steven.djordjevic@uts.edu.au.
authors.forename: Steven P
authors.initials: SP
authors.lastname: Djordjevic
keywords: Mpn142; Mycoplasma pneumoniae M129 strain; P40 and P90; ectodomain shedding; endoproteolysis; multifunctional proteins; protein disorder; protein processing; proteins B and C