title: Decoding the folding of Burkholderia glumae lipase: folding intermediates en route to kinetic stability.
abstract: The lipase produced by Burkholderia glumae folds spontaneously into an inactive near-native state and requires a periplasmic chaperone to reach its final active and secretion-competent fold. The B. glumae lipase-specific foldase (Lif) is classified as a member of the steric-chaperone family of which the propeptides of α-lytic protease and subtilisin are the best known representatives. Steric chaperones play a key role in conferring kinetic stability to proteins. However, until present there was no solid experimental evidence that Lif-dependent lipases are kinetically trapped enzymes. By combining thermal denaturation studies with proteolytic resistance experiments and the description of distinct folding intermediates, we demonstrate that the native lipase has a kinetically stable conformation. We show that a newly discovered molten globule-like conformation has distinct properties that clearly differ from those of the near-native intermediate state. The folding fingerprint of Lif-dependent lipases is put in the context of the protease-prodomain system and the comparison reveals clear differences that render the lipase-Lif systems unique. Limited proteolysis unveils structural differences between the near-native intermediate and the native conformation and sets the stage to shed light onto the nature of the kinetic barrier.
authors.affiliation: Department of Structural Biology, VIB and Vrije Universiteit Brussel, Brussels, Belgium. krpauwel@vib-vub.be
authors.forename: Kris
authors.initials: K
authors.lastname: Pauwels
authors.forename: Manuel M
authors.initials: MM
authors.lastname: Sanchez del Pino
authors.forename: Georges
authors.initials: G
authors.lastname: Feller
authors.forename: Patrick
authors.initials: P
authors.lastname: Van Gelder
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism*; D019117:Burkholderia / Q000201:enzymology*; D007700:Kinetics; D008049:Lipase / Q000737:chemistry* / Q000378:metabolism; D018832:Molecular Chaperones / Q000378:metabolism; D011487:Protein Conformation; D017510:Protein Folding; D059748:Proteolysis
chemical_list: D001426:Bacterial Proteins; D018832:Molecular Chaperones; D008049:Lipase