title: Biophysical characterization of the recombinant merozoite surface protein-3 of Plasmodium vivax.
abstract: Plasmodium vivax Merozoite Surface Protein-3alpha and 3beta are members of a family of related merozoite surface proteins that contain a central alanine-rich domain with heptad repeats that is predicted to form alpha-helical secondary and coiled-coil tertiary structures. Seven recombinant proteins representing different regions of MSP-3alpha and MSP-3beta of P. vivax were generated to investigate their structure. Circular dichroism spectra analysis revealed that some proteins are folded with a high degree of alpha-helices as secondary structure, whereas other products contain a high content of random coil. Using size exclusion chromatography, we found that the two smaller fragments of the MSP-3alpha, named CC4 and CC5, predicted to form coiled-coil (CC) structures, eluted at volumes corresponding to molecular weights larger than their monomeric masses. This result suggests that both proteins are oligomeric molecules. Analytical ultracentrifugation experiments showed that the CC5 oligomers are elongated molecules. Together, these data may help to understand important aspects of P. vivax biology.
authors.affiliation: Departamento de Análises Clínicas e Toxicológicas, Faculdade de Ciências Farmacêuticas, Universidade de São Paulo, Av. Prof. Lineu Prestes, 580, Cidade Universitária, São Paulo, SP, 05508-900, Brazil.
authors.forename: Maria Carolina S
authors.initials: MC
authors.lastname: Jimenez
authors.forename: Carlos Henrique I
authors.initials: CH
authors.lastname: Ramos
authors.forename: João Alexandre R G
authors.initials: JA
authors.lastname: Barbosa
authors.forename: Mary R
authors.initials: MR
authors.lastname: Galinski
authors.forename: John W
authors.initials: JW
authors.lastname: Barnwell
authors.forename: Mauricio M
authors.initials: MM
authors.lastname: Rodrigues
authors.forename: Irene S
authors.initials: IS
authors.lastname: Soares
mesh_terms: D000409:Alanine / Q000737:chemistry; D000818:Animals; D000953:Antigens, Protozoan / Q000737:chemistry* / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D001703:Biophysics / Q000379:methods*; D002942:Circular Dichroism; D010957:Plasmids; D010966:Plasmodium vivax / Q000737:chemistry* / Q000235:genetics; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D015800:Protozoan Proteins / Q000737:chemistry* / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D000953:Antigens, Protozoan; D015800:Protozoan Proteins; D011993:Recombinant Fusion Proteins; C089133:merozoite surface protein 3, Plasmodium; D000409:Alanine