title: Dynamic Motion and Communication in the Streptococcal C1 Phage Lysin, PlyC.
abstract: The growing problem of antibiotic resistance underlies the critical need to develop new treatments to prevent and control resistant bacterial infection. Exogenous application of bacteriophage lysins results in rapid and specific destruction of Gram-positive bacteria and therefore lysins represent novel antibacterial agents. The PlyC phage lysin is the most potent lysin characterized to date and can rapidly lyse Group A, C and E streptococci. Previously, we have determined the X-ray crystal structure of PlyC, revealing a complicated and unique arrangement of nine proteins. The scaffold features a multimeric cell-wall docking assembly bound to two catalytic domains that communicate and work synergistically. However, the crystal structure appeared to be auto-inhibited and raised important questions as to the mechanism underlying its extreme potency. Here we use small angle X-ray scattering (SAXS) and reveal that the conformational ensemble of PlyC in solution is different to that in the crystal structure. We also investigated the flexibility of the enzyme using both normal mode (NM) analysis and molecular dynamics (MD) simulations. Consistent with our SAXS data, MD simulations show rotational dynamics of both catalytic domains, and implicate inter-domain communication in achieving a substrate-ready conformation required for enzyme function. Our studies therefore provide insights into how the domains in the PlyC holoenzyme may act together to achieve its extraordinary potency.
authors.affiliation: Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia.
authors.forename: Blake T
authors.initials: BT
authors.lastname: Riley
authors.affiliation: Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia.
authors.forename: Sebastian S
authors.initials: SS
authors.lastname: Broendum
authors.affiliation: Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia; Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Australia.
authors.forename: Cyril F
authors.initials: CF
authors.lastname: Reboul
authors.affiliation: Australian Synchrotron, Clayton, Australia.
authors.forename: Nathan P
authors.initials: NP
authors.lastname: Cowieson
authors.affiliation: Programa de Computação Científica, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil.
authors.forename: Mauricio G S
authors.initials: MG
authors.lastname: Costa
authors.affiliation: Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia; Victorian Life Sciences Computation Initiative Life Sciences Computation Centre, Monash University, Clayton, Australia.
authors.forename: Itamar
authors.initials: I
authors.lastname: Kass
authors.affiliation: Research School of Chemistry, Australian National University, Canberra, Australia.
authors.forename: Colin
authors.initials: C
authors.lastname: Jackson
authors.affiliation: Laboratoire de Biologie et de Pharmacologie Appliquée, Ecole Normale Supérieure de Cachan, Centre National de la Recherche Scientifique, Cachan, France.
authors.forename: David
authors.initials: D
authors.lastname: Perahia
authors.affiliation: Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia.
authors.forename: Ashley M
authors.initials: AM
authors.lastname: Buckle
authors.affiliation: Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia; Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Australia.
authors.forename: Sheena
authors.initials: S
authors.lastname: McGowan
mesh_terms: D001435:Bacteriophages / Q000737:chemistry / Q000201:enzymology*; D020134:Catalytic Domain; D018360:Crystallography, X-Ray / Q000379:methods; D004798:Enzymes / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D056004:Molecular Dynamics Simulation; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D053838:Scattering, Small Angle; D013291:Streptococcus / Q000821:virology*
chemical_list: D004798:Enzymes; C028806:lysin, streptococcus bacteriophage