title: Nanoscale topography of hepatitis B antigen particles by atomic force microscopy.
abstract: Hepatitis B virus envelope is mainly composed of three forms of the same protein expressed from different start codons of the same open reading frame. The smaller form named S protein corresponds to the C-terminal common region and represents about 80% of the envelope proteins. It is mainly referred as hepatitis B virus surface antigen (HBsAg). Over expressed in the host cell, this protein can be produced as spherical and tubular self-organized particles. Highly immunogenic, these particles are used in licensed hepatitis B vaccines. In this study we have combined transmission electron microscopy and atomic force microscopy to determine the shape and size of HBsAg particles produced from the yeast Hansenula polymorpha. Tapping mode atomic force microscopy in liquid allows structural details of the surface to be delineated with a resolution in the nanometer range. Particles were decorated by closely packed spike-like structures protruding from particle surface. Protrusions appeared uniformly distributed at the surface and an average number of 75 protrusions per particle were calculated. Importantly, we demonstrated that proteins mainly contribute to the topography of the protrusions.
authors.affiliation: Inserm, Unité 554, Montpellier, France. pem@cbs.cnrs.fr
authors.forename: Pierre-Emmanuel
authors.initials: PE
authors.lastname: Milhiet
authors.forename: Patrice
authors.initials: P
authors.lastname: Dosset
authors.forename: Cédric
authors.initials: C
authors.lastname: Godefroy
authors.forename: Christian
authors.initials: C
authors.lastname: Le Grimellec
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Guigner
authors.forename: Eric
authors.initials: E
authors.lastname: Larquet
authors.forename: Frédéric
authors.initials: F
authors.lastname: Ronzon
authors.forename: Catherine
authors.initials: C
authors.lastname: Manin
mesh_terms: D004229:Dithiothreitol / Q000378:metabolism; D006511:Hepatitis B Antigens / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D018625:Microscopy, Atomic Force / Q000379:methods*; D008854:Microscopy, Electron; D036103:Nanotechnology / Q000379:methods*; D010843:Pichia / Q000235:genetics
chemical_list: D006511:Hepatitis B Antigens; D004229:Dithiothreitol