title: Stability of the octameric structure affects plasminogen-binding capacity of streptococcal enolase.
abstract: Group A Streptococcus (GAS) is a human pathogen that has the potential to cause invasive disease by binding and activating human plasmin(ogen). Streptococcal surface enolase (SEN) is an octameric α-enolase that is localized at the GAS cell surface. In addition to its glycolytic role inside the cell, SEN functions as a receptor for plasmin(ogen) on the bacterial surface, but the understanding of the molecular basis of plasmin(ogen) binding is limited. In this study, we determined the crystal and solution structures of GAS SEN and characterized the increased plasminogen binding by two SEN mutants. The plasminogen binding ability of SENK312A and SENK362A is ~2- and ~3.4-fold greater than for the wild-type protein. A combination of thermal stability assays, native mass spectrometry and X-ray crystallography approaches shows that increased plasminogen binding ability correlates with decreased stability of the octamer. We propose that decreased stability of the octameric structure facilitates the access of plasmin(ogen) to its binding sites, leading to more efficient plasmin(ogen) binding and activation.
authors: School of Chemistry and Molecular Biosciences and Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, 4072, Australia; Australian Infectious Disease Research Centre, University of Queensland, Brisbane, QLD, 4072, Australia.
authors: Amanda J
authors: AJ
authors: Cork
authors: School of Chemistry and Molecular Biosciences and Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, 4072, Australia; Australian Infectious Disease Research Centre, University of Queensland, Brisbane, QLD, 4072, Australia.
authors: Daniel J
authors: DJ
authors: Ericsson
authors: Department of Biochemistry and Molecular Biology and the ARC Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Melbourne, VIC, 3800, Australia.
authors: Ruby H P
authors: RH
authors: Law
authors: School of Chemistry and Molecular Biosciences and Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, 4072, Australia.
authors: Lachlan W
authors: LW
authors: Casey
authors: School of Chemistry and Molecular Biosciences and Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, 4072, Australia.
authors: Eugene
authors: E
authors: Valkov
authors: School of Chemistry and Molecular Biosciences and Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, 4072, Australia.
authors: Carlo
authors: C
authors: Bertozzi
authors: School of Chemistry and Molecular Biosciences and Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, 4072, Australia.
authors: Anna
authors: A
authors: Stamp
authors: School of Biological Sciences and Illawarra Health and Medical Research, University of Wollongong, Wollongong, NSW, 2522, Australia.
authors: Blagojce
authors: B
authors: Jovcevski
authors: School of Biological Sciences and Illawarra Health and Medical Research, University of Wollongong, Wollongong, NSW, 2522, Australia.
authors: J Andrew
authors: JA
authors: Aquilina
authors: Department of Biochemistry and Molecular Biology and the ARC Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Melbourne, VIC, 3800, Australia.
authors: James C
authors: JC
authors: Whisstock
authors: School of Chemistry and Molecular Biosciences and Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, 4072, Australia; Australian Infectious Disease Research Centre, University of Queensland, Brisbane, QLD, 4072, Australia.
authors: Mark J
authors: MJ
authors: Walker
authors: School of Chemistry and Molecular Biosciences and Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, 4072, Australia; Australian Infectious Disease Research Centre, University of Queensland, Brisbane, QLD, 4072, Australia.
authors: Bostjan
authors: B
authors: Kobe
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D018360:Crystallography, X-Ray; D006801:Humans; D010751:Phosphopyruvate Hydratase / Q000378:metabolism*; D010958:Plasminogen / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation; D013297:Streptococcus pyogenes / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D010958:Plasminogen; C112984:streptococcal surface enolase; D010751:Phosphopyruvate Hydratase