title: Substrate occupancy at the onset of oligomeric transitions of DegP.
abstract: The protease-chaperone DegP undergoes secondary through quaternary structural changes, regulating function and preventing indiscriminate proteolysis. Several structures of DegP oligomers have been observed, including the resting state 6-mer and the 12-mer and 24-mer active states. However, the precise events of the transition between the resting and active states still need to be elucidated. We used native mass spectrometry to demonstrate that binding of multiple substrate-mimicking peptide ligands to the DegP resting state occurs prior to the transition to an active conformation. This transition occurred at a 6-mer occupancy of 40% for each peptide ligand. We observed ligand-specific 9-mer formation with a maximum load of 9 peptides, whereas other substrates led to 12-mers accommodating 24 peptides. Based on these data, we present a model for the initial steps of substrate-induced transitions from the resting to active states of DegP.
authors.affiliation: Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute of Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands; Netherlands Proteomics Centre, Padualaan 8, 3584 CH Utrecht, the Netherlands.
authors.forename: Natalie J
authors.initials: NJ
authors.lastname: Thompson
authors.affiliation: Faculty of Biology, Center for Medical Biotechnology, University Duisburg-Essen, 45117 Essen, Germany.
authors.forename: Melisa
authors.initials: M
authors.lastname: Merdanovic
authors.affiliation: Faculty of Biology, Center for Medical Biotechnology, University Duisburg-Essen, 45117 Essen, Germany; School of Biosciences, Cardiff University, Cardiff CF10 3US, UK.
authors.forename: Michael
authors.initials: M
authors.lastname: Ehrmann
authors.affiliation: Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute of Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands; Netherlands Proteomics Centre, Padualaan 8, 3584 CH Utrecht, the Netherlands.
authors.forename: Esther
authors.initials: E
authors.lastname: van Duijn
authors.affiliation: Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute of Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands; Netherlands Proteomics Centre, Padualaan 8, 3584 CH Utrecht, the Netherlands. Electronic address: a.j.r.heck@uu.nl.
authors.forename: Albert J R
authors.initials: AJ
authors.lastname: Heck
mesh_terms: D000595:Amino Acid Sequence; D004926:Escherichia coli / Q000201:enzymology*; D006360:Heat-Shock Proteins / Q000737:chemistry*; D008024:Ligands; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry; D033903:Periplasmic Proteins / Q000737:chemistry*; D011485:Protein Binding; D017510:Protein Folding; D020836:Protein Structure, Quaternary; D012697:Serine Endopeptidases / Q000737:chemistry*; D013379:Substrate Specificity
chemical_list: D006360:Heat-Shock Proteins; D008024:Ligands; D010455:Peptides; D033903:Periplasmic Proteins; C061682:DegP protease; D012697:Serine Endopeptidases