title: Secreted glycoprotein from Live Zaire ebolavirus-infected cultures: preparation, structural and biophysical characterization, and thermodynamic stability.
abstract: Milligram quantities of Zaire ebolavirus nonstructural, secreted glycoprotein (sGP) were purified to homogeneity, and this preparation was characterized by an array of biophysical and biochemical experiments. Mass-spectrometry analysis revealed sGP posttranslational modifications and regions susceptible to limited proteolysis. In solution, sGP has an absolute molar mass of 103 kDa, is monodisperse, and folds into a predominantly beta -sheet conformation with a distinct tertiary structure. sGP appears to have a unique free-energy landscape that facilitates reversible folding and a strong propensity for disulfide-linked dimeric quaternary structure under a wide range of conditions; the low apparent free energy of conformation transition of sGP ( Delta G=1.7+/-0.1 kcal/mol) suggests that the molecule is well suited as a thermodynamically facile switch, which would allow it to report on relatively subtle changes in milieu. In addition, a conformational transition at 37 degrees C was detected in thermal denaturing experiments. On the basis of biophysical and biochemical considerations alone, we propose that the property of being a thermodynamically facile switch is an important clue to reveal sGP functionality.
authors.affiliation: Special Pathogens Branch, Division of Viral and Rickettsial Diseases, National Center for Zoonotic, Vector-Borne, and Enteric Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA. LBarrientos1@cdc.gov
authors.forename: Laura G
authors.initials: LG
authors.lastname: Barrientos
authors.forename: Amy M
authors.initials: AM
authors.lastname: Martin
authors.forename: Robert M
authors.initials: RM
authors.lastname: Wohlhueter
authors.forename: Pierre E
authors.initials: PE
authors.lastname: Rollin
mesh_terms: D000818:Animals; D055592:Biophysical Phenomena; D001703:Biophysics; D002522:Chlorocebus aethiops; D015023:Democratic Republic of the Congo; D004355:Drug Stability; D029043:Ebolavirus / Q000302:isolation & purification / Q000502:physiology*; D006023:Glycoproteins / Q000737:chemistry* / Q000378:metabolism*; D000882:Haplorhini; D011487:Protein Conformation; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013816:Thermodynamics; D014709:Vero Cells; D014764:Viral Proteins / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D006023:Glycoproteins; D014764:Viral Proteins