title: Crystallization and preliminary X-ray analysis of the Plasmodium vivax sexual stage 25 kDa protein Pvs25, a transmission-blocking vaccine candidate for malaria.
abstract: The Plasmodium vivax sexual stage 25 kDa protein Pvs25 is expressed on the surface of the ookinete form of the parasite. Monoclonal antibodies directed against Pvs25 block the development of P. vivax oocysts in the mosquito host. Thus, Pvs25 is a potential vaccine candidate for eliciting transmission-blocking immunity in individuals living in malaria-epidemic regions. Pvs25 which was expressed and purified for clinical trials was crystallized using polyethylene glycol as the precipitating agent and diffracts X-rays to 2.3 A. The orthorhombic Pvs25 crystal form belongs to space group P2(1)2(1)2(1), with unit-cell parameters a = 42.6, b = 59.8, c = 66.8 A and one molecule in the asymmetric unit. Reductively methylated Pvs25 crystallized in two forms: an orthorhombic P2(1)2(1)2(1) form with unit-cell parameters a = 43.4, b = 62.9, c = 66.9 A and one molecule in the asymmetric unit and a monoclinic P2(1) form with unit-cell parameters a = 53.5, b = 43.3, c = 65.3 A, beta = 104.0 degrees which was predicted to have one or two molecules in the asymmetric unit. Several native and heavy-atom data sets have been collected from Pvs25 and methylated Pvs25 crystals for use in MAD or MIR techniques.
authors.affiliation: Structural Biology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Twinbrook II, 12441 Parklawn Drive, Rockville, Maryland 20852, USA.
authors.forename: Ajay K
authors.initials: AK
authors.lastname: Saxena
authors.forename: Allan
authors.initials: A
authors.lastname: Saul
authors.forename: David N
authors.initials: DN
authors.lastname: Garboczi
mesh_terms: D000818:Animals; D000953:Antigens, Protozoan / Q000737:chemistry; D000954:Antigens, Surface / Q000737:chemistry; D003001:Cloning, Molecular; D003460:Crystallization; D018360:Crystallography, X-Ray; D017780:Malaria Vaccines / Q000737:chemistry; D008745:Methylation; D010966:Plasmodium vivax / Q000737:chemistry*; D015800:Protozoan Proteins / Q000737:chemistry*
chemical_list: D000953:Antigens, Protozoan; D000954:Antigens, Surface; D017780:Malaria Vaccines; D015800:Protozoan Proteins; C121473:Pvs25 protein, P vivax; C064783:sexual stage specific protein, Plasmodium