| Author |
Badarau, Adriana Hoffman, David Rouha, Harald Jägerhofer, Michaela Maierhofer, Barbara Håkansson, Maria Teubenbacher, Astrid Malafa, Stefan Dolezilkova, Ivana Weber, Susanne Nagy, Eszter Stulik, Lukas Gross, Karin Logan, Derek T. |
| Description |
Author Affiliation: Badarau A ( From Arsanis Biosciences, Vienna Biocenter Campus, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria and.); Rouha H ( From Arsanis Biosciences, Vienna Biocenter Campus, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria and.); Malafa S ( From Arsanis Biosciences, Vienna Biocenter Campus, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria and.); Logan DT ( SARomics Biostructures AB, Medicon Village, S-223 81 Lund, Sweden.); Håkansson M ( SARomics Biostructures AB, Medicon Village, S-223 81 Lund, Sweden.); Stulik L ( From Arsanis Biosciences, Vienna Biocenter Campus, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria and.); Dolezilkova I ( From Arsanis Biosciences, Vienna Biocenter Campus, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria and.); Teubenbacher A ( From Arsanis Biosciences, Vienna Biocenter Campus, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria and.); Gross K ( From Arsanis Biosciences, Vienna Biocenter Campus, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria and.); Maierhofer B ( From Arsanis Biosciences, Vienna Biocenter Campus, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria and.); Weber S ( From Arsanis Biosciences, Vienna Biocenter Campus, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria and.); Jägerhofer M ( From Arsanis Biosciences, Vienna Biocenter Campus, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria and.); Hoffman D ( From Arsanis Biosciences, Vienna Biocenter Campus, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria and.); Nagy E ( From Arsanis Biosciences, Vienna Biocenter Campus, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria and eszter.nagy@arsanis.com.) |
| Abstract |
The bi-component leukocidins of Staphylococcus aureus are important virulence factors that lyse human phagocytic cells and contribute to immune evasion. The γ-hemolysins (HlgAB and HlgCB) and Panton-Valentine leukocidin (PVL or LukSF) were shown to assemble from soluble subunits into membrane-bound oligomers on the surface of target cells, creating barrel-like pore structures that lead to cell lysis. LukGH is the most distantly related member of this toxin family, sharing only 30-40% amino acid sequence identity with the others. We observed that, unlike other leukocidin subunits, recombinant LukH and LukG had low solubility and were unable to bind to target cells, unless both components were present. Using biolayer interferometry and intrinsic tryptophan fluorescence we detected binding of LukH to LukG in solution with an affinity in the low nanomolar range and dynamic light scattering measurements confirmed formation of a heterodimer. We elucidated the structure of LukGH by x-ray crystallography at 2.8-Šresolution. This revealed an octameric structure that strongly resembles that reported for HlgAB, but with important structural differences. Structure guided mutagenesis studies demonstrated that three salt bridges, not found in other bi-component leukocidins, are essential for dimer formation in solution and receptor binding. We detected weak binding of LukH, but not LukG, to the cellular receptor CD11b by biolayer interferometry, suggesting that in common with other members of this toxin family, the S-component has the primary contact role with the receptor. These new insights provide the basis for novel strategies to counteract this powerful toxin and Staphylococcus aureus pathogenesis. |
| Subject Keyword |
Antigens, CD11b Chemistry Bacterial Proteins Hemolysin Proteins Leukocidins Staphylococcus Aureus Amino Acid Sequence Animals Metabolism Binding Sites Crystallography, X-Ray HL-60 Cells Mice Models, Molecular Molecular Sequence Data Mutation Protein Binding Protein Multimerization Protein Structure, Secondary Protein Structure, Tertiary Recombinant Proteins Sequence Alignment Sequence Homology, Amino Acid Structure-Activity Relationship Research Support, Non-U.S. Gov't Biochemistry Molecular Biology |
