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Streptococcal M1 protein constructs a pathological host fibrinogen network


M1 protein, a major virulence factor of the leading invasive strain of group A Streptococcus, is sufficient to induce toxic-shock-like vascular leakage and tissue injury. These events are triggered by the formation of a complex between M1 and fibrinogen that, unlike M1 or fibrinogen alone, leads to neutrophil activation. Here we provide a structural explanation for the pathological properties of the complex formed between streptococcal M1 and human fibrinogen. A conformationally dynamic coiled-coil dimer of M1 was found to organize four fibrinogen molecules into a specific cross-like pattern. This pattern supported the construction of a supramolecular network that was required for neutrophil activation but was distinct from a fibrin clot. Disruption of this network into other supramolecular assemblies was not tolerated. These results have bearing on the pathophysiology of streptococcal toxic shock.

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Figure 1: M1 assembles fibrinogen into a cross-like pattern.
Figure 2: M1–fibrinogen interface.
Figure 3: Conformational dynamics.
Figure 4: M1–fibrinogen network.
Figure 5: Fibrinogen binding and neutrophil activation.

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  1. 1

    Fischetti, V. A. Streptococcal M protein: molecular design and biological behavior. Clin. Microbiol. Rev. 2, 285–314 (1989)

    CAS  Article  Google Scholar 

  2. 2

    Cunningham, M. W. Pathogenesis of group A streptococcal infections. Clin. Microbiol. Rev. 13, 470–511 (2000)

    CAS  Article  Google Scholar 

  3. 3

    Facklam, R. F. et al. Extension of the Lancefield classification for group A streptococci by addition of 22 new M protein gene sequence types from clinical isolates: emm103 to emm124. Clin. Infect. Dis. 34, 28–38 (2002)

    CAS  Article  Google Scholar 

  4. 4

    Steer, A. C., Law, I., Matatolu, L., Beall, B. W. & Carapetis, J. R. Global emm type distribution of group A streptococci: systematic review and implications for vaccine development. Lancet Infect. Dis. 9, 611–616 (2009)

    Article  Google Scholar 

  5. 5

    Aziz, R. K. & Kotb, M. Rise and persistence of global M1T1 clone of Streptococcus pyogenes . Emerg. Infect. Dis. 14, 1511–1517 (2008)

    CAS  Article  Google Scholar 

  6. 6

    Herwald, H. et al. M protein, a classical bacterial virulence determinant, forms complexes with fibrinogen that induce vascular leakage. Cell 116, 367–379 (2004)

    CAS  Article  Google Scholar 

  7. 7

    Kahn, F. et al. Antibodies against a surface protein of Streptococcus pyogenes promote a pathological inflammatory response. PLoS Pathog. 4, e1000149 (2008)

    Article  Google Scholar 

  8. 8

    McNamara, C. et al. Coiled-coil irregularities and instabilities in group A Streptococcus M1 are required for virulence. Science 319, 1405–1408 (2008)

    ADS  CAS  Article  Google Scholar 

  9. 9

    Soehnlein, O. et al. Neutrophil degranulation mediates severe lung damage triggered by streptococcal M1 protein. Eur. Respir. J. 32, 405–412 (2008)

    CAS  Article  Google Scholar 

  10. 10

    Gautam, N. et al. Heparin-binding protein (HBP/CAP37): a missing link in neutrophil-evoked alteration of vascular permeability. Nature Med. 7, 1123–1127 (2001)

    CAS  Article  Google Scholar 

  11. 11

    Linder, A., Christensson, B., Herwald, H., Bjorck, L. & Akesson, P. Heparin-binding protein: an early marker of circulatory failure in sepsis. Clin. Infect. Dis. 49, 1044–1050 (2009)

    CAS  Article  Google Scholar 

  12. 12

    Shannon, O. et al. Severe streptococcal infection is associated with M protein-induced platelet activation and thrombus formation. Mol. Microbiol. 65, 1147–1157 (2007)

    CAS  Article  Google Scholar 

  13. 13

    Spraggon, G., Everse, S. J. & Doolittle, R. F. Crystal structures of fragment D from human fibrinogen and its crosslinked counterpart from fibrin. Nature 389, 455–462 (1997)

    ADS  CAS  Article  Google Scholar 

  14. 14

    Bowley, S. R. & Lord, S. T. Fibrinogen variant BßD432A has normal polymerization but does not bind knob “B”. Blood 113, 4425–4430 (2009)

    CAS  Article  Google Scholar 

  15. 15

    Ringdahl, U. et al. A role for the fibrinogen-binding regions of streptococcal M proteins in phagocytosis resistance. Mol. Microbiol. 37, 1318–1326 (2000)

    CAS  Article  Google Scholar 

  16. 16

    Akesson, P., Schmidt, K. H., Cooney, J. & Bjorck, L. M1 protein and protein H: IgGFc- and albumin-binding streptococcal surface proteins encoded by adjacent genes. Biochem. J. 300, 877–886 (1994)

    Article  Google Scholar 

  17. 17

    Medved, L., Litvinovich, S., Ugarova, T., Matsuka, Y. & Ingham, K. Domain structure and functional activity of the recombinant human fibrinogen γ-module (γ148–411). Biochemistry 36, 4685–4693 (1997)

    CAS  Article  Google Scholar 

  18. 18

    Lupas, A., Van Dyke, M. & Stock, J. Predicting coiled coils from protein sequences. Science 252, 1162–1164 (1991)

    ADS  CAS  Article  Google Scholar 

  19. 19

    Tripet, B., Wagschal, K., Lavigne, P., Mant, C. T. & Hodges, R. S. Effects of side-chain characteristics on stability and oligomerization state of a de novo-designed model coiled-coil: 20 amino acid substitutions in position “d”. J. Mol. Biol. 300, 377–402 (2000)

    CAS  Article  Google Scholar 

  20. 20

    Wagschal, K., Tripet, B., Lavigne, P., Mant, C. & Hodges, R. S. The role of position a in determining the stability and oligomerization state of α-helical coiled coils: 20 amino acid stability coefficients in the hydrophobic core of proteins. Protein Sci. 8, 2312–2329 (1999)

    CAS  Article  Google Scholar 

  21. 21

    Kollman, J. M., Pandi, L., Sawaya, M. R., Riley, M. & Doolittle, R. F. Crystal structure of human fibrinogen. Biochemistry 48, 3877–3886 (2009)

    CAS  Article  Google Scholar 

  22. 22

    Navarre, W. W. & Schneewind, O. Surface proteins of gram-positive bacteria and mechanisms of their targeting to the cell wall envelope. Microbiol. Mol. Biol. Rev. 63, 174–229 (1999)

    CAS  PubMed  PubMed Central  Google Scholar 

  23. 23

    Gautam, N., Herwald, H., Hedqvist, P. & Lindbom, L. Signaling via β2 integrins triggers neutrophil-dependent alteration in endothelial barrier function. J. Exp. Med. 191, 1829–1840 (2000)

    CAS  Article  Google Scholar 

  24. 24

    Whitnack, E. & Beachey, E. H. Inhibition of complement-mediated opsonization and phagocytosis of Streptococcus pyogenes by D fragments of fibrinogen and fibrin bound to cell surface M protein. J. Exp. Med. 162, 1983–1997 (1985)

    CAS  Article  Google Scholar 

  25. 25

    Lishko, V. K., Kudryk, B., Yakubenko, V. P., Yee, V. C. & Ugarova, T. P. Regulated unmasking of the cryptic binding site for integrin αMβ2 in the γC-domain of fibrinogen. Biochemistry 41, 12942–12951 (2002)

    CAS  Article  Google Scholar 

  26. 26

    Leslie, A. Recent changes to the MOSFLM package for processing film and image plate data. Joint CCP4 ESF-EAMCB Newslett. Protein Crystallogr. 26, (1992)

  27. 27

    Otwinowski, Z. & Minor, W. Processing of X-ray diffraction data collected in oscillation mode. Methods Enzymol. 276, 307–326 (1997)

    CAS  Article  Google Scholar 

  28. 28

    McCoy, A. J. et al. Phaser crystallographic software. J. Appl. Cryst. 40, 658–674 (2007)

    CAS  Article  Google Scholar 

  29. 29

    Kansal, R. G., McGeer, A., Low, D. E., Norrby-Teglund, A. & Kotb, M. Inverse relation between disease severity and expression of the streptococcal cysteine protease, SpeB, among clonal M1T1 isolates recovered from invasive group A streptococcal infection cases. Infect. Immun. 68, 6362–6369 (2000)

    CAS  Article  Google Scholar 

  30. 30

    Geiser, M., Cebe, R., Drewello, D. & Schmitz, R. Integration of PCR fragments at any specific site within cloning vectors without the use of restriction enzymes and DNA ligase. Biotechniques 31, 88–90. 92 (2001)

    CAS  Article  Google Scholar 

  31. 31

    Doublié, S. Preparation of selenomethionyl proteins for phase determination in Methods in Enzymology 276, 523–530 (Academic, 1997)

    Google Scholar 

  32. 32

    Everse, S. J., Pelletier, H. & Doolittle, R. F. Crystallization of fragment D from human fibrinogen. Protein Sci. 4, 1013–1016 (1995)

    CAS  Article  Google Scholar 

  33. 33

    CCP4. The CCP4 suite: programs for protein crystallography. Acta Crystallogr. D 50, 760–763 (1994)

  34. 34

    DeLaBarre, B. & Brunger, A. T. Considerations for the refinement of low-resolution crystal structures. Acta Crystallogr. D 62, 923–932 (2006)

    Article  Google Scholar 

  35. 35

    Brünger, A. Crystallography & NMR system: a new software for macromolecular structure determination. Acta Crystallogr. D 54, 905–921 (1998)

    Article  Google Scholar 

  36. 36

    Brünger, A. T. Free R value: a novel statistical quantity for assessing the accuracy of crystal structures. Nature 355, 472–475 (1992)

    ADS  Article  Google Scholar 

  37. 37

    Brünger, A. T., Adams, P. D. & Rice, L. M. New applications of simulated annealing in X-ray crystallography and solution NMR. Structure 5, 325–336 (1997)

    Article  Google Scholar 

  38. 38

    Emsley, P. & Cowtan, K. Coot: model-building tools for molecular graphics. Acta Crystallogr. D 60, 2126–2132 (2004)

    Article  Google Scholar 

  39. 39

    Laskowski, R. A., Moss, D. S. & Thornton, J. M. Main-chain bond lengths and bond angles in protein structures. J. Mol. Biol. 231, 1049–1067 (1993)

    CAS  Article  Google Scholar 

  40. 40

    Chen, V. B. et al. MolProbity: all-atom structure validation for macromolecular crystallography. Acta Crystallogr. D 66, 12–21 (2010)

    CAS  Article  Google Scholar 

  41. 41

    Yang, Z., Kollman, J. M., Pandi, L. & Doolittle, R. F. Crystal structure of native chicken fibrinogen at 2.7 Å resolution. Biochemistry 40, 12515–12523 (2001)

    CAS  Article  Google Scholar 

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We thank the Argonne Photon Source Laboratory GM/CA CAT staff for help with data collection, R. Doolittle and A. Royant for advice, and S. Mel and G. Ghosh for comments on the manuscript. This work was supported by NIH R21 AI071167 (P.G.), T32 GM007240 (C.B.), R01 AI077780 (V.N.), R01 GM54076 (J.E.J.), and a fellowship (J.N.C.) from the National Health and Medical Research Council of Australia (514639).

Author information




P.M. and P.G. designed the experiments. P.M. carried out the structure determination, modelling and FgD co-precipitation assay. C.B. carried out the Fc co-precipitation assay. P.M. and C.-y.F. carried out the electron microscopy under the supervision of J.E.J. P.M., A.S.Z. and J.N.C. carried out the HBP release assays under the supervision of V.N. P.M. and P.G. wrote the manuscript, and the other authors provided editorial advice.

Corresponding author

Correspondence to Partho Ghosh.

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The authors declare no competing financial interests.

Additional information

Atomic coordinates and structure factors for M1BC1–FgD (2XNX) and M1A–FgD (2XNY) have been deposited with the Protein Data Bank.

Supplementary information

Supplementary Information

This file is contains Supplementary Table 1 and Supplementary Figures 1-7 with legends. (PDF 5524 kb)

Supplementary Movie 1

The movie shows the M1-Fg network in surface representation (M1 in red, Fg in blue). (MOV 7898 kb)

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Macheboeuf, P., Buffalo, C., Fu, Cy. et al. Streptococcal M1 protein constructs a pathological host fibrinogen network. Nature 472, 64–68 (2011).

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