P40 and P90 from Mpn142 are Targets of Multiple Processing Events on the Surface of Mycoplasma pneumoniae

Proteomes

Michael Widjaja²  Iain J. Berry²  Elsa J. Pont²  Matthew P. Padula¹  Steven P. Djordjevic²  Michael Hecker³ 

[1] Proteomics Core Facility, University of Technology Sydney, Cnr Harris and Thomas St, Ultimo, NSW 2007, Australia; E-Mail:;ithree institute, University of Technology Sydney, P.O. Box 123 Broadway, Ultimo, NSW 2007, Australia; E-Mails:ithree institute, University of Technology Sydney, P.O. Box 123 Broadway, Ultimo, NSW 2007, Australia;

关键词: ectodomain shedding;    protein processing;    multifunctional proteins;    Mycoplasma pneumoniae M129 strain;    P40 and P90;    proteins B and C;    Mpn142;    protein disorder;    endoproteolysis;   

DOI  :  10.3390/proteomes3040512

来源: mdpi

【 摘 要 】

Mycoplasma pneumoniae is a significant cause of community acquired pneumonia globally. Despite having a genome less than 1 Mb in size, M. pneumoniae presents 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 of M. pneumoniae identified 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 of M. pneumoniae were 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.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.