title: A critical step in the folding of influenza virus HA determined with a novel folding assay.
abstract: Most principles of protein folding emerged from refolding studies in vitro on small, soluble proteins, because large ones tend to misfold and aggregate. We developed a folding assay allowing the study of large proteins in detergent such that the extent of cellular assistance required for proper folding can be determined. We identified a critical step in the in vivo folding pathway of influenza virus hemagglutinin (HA). Only the formation of the first few disulfides in the top domain of HA required the intact endoplasmic reticulum. After that, HA proceeded to fold efficiently in a very dilute solution, despite its size and complexity. This study paves the way for detailed structural analyses during the folding of complex proteins.
authors.affiliation: Department of Cellular Protein Chemistry, Bijvoet Center for Biomolecular Research, Faculty of Chemistry, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
authors.forename: M Claudia
authors.initials: MC
authors.lastname: Maggioni
authors.forename: I Marije
authors.initials: IM
authors.lastname: Liscaljet
authors.forename: Ineke
authors.initials: I
authors.lastname: Braakman
mesh_terms: D000818:Animals; D000906:Antibodies / Q000276:immunology; D016466:CHO Cells; D037281:Calnexin / Q000737:chemistry; D037282:Calreticulin / Q000737:chemistry; D002474:Cell-Free System; D006224:Cricetinae; D003412:Cricetulus; D004220:Disulfides / Q000737:chemistry; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000737:chemistry* / Q000276:immunology; D011487:Protein Conformation; D017510:Protein Folding
chemical_list: D000906:Antibodies; D037282:Calreticulin; D004220:Disulfides; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D037281:Calnexin