Secreted Glycoprotein from Live Zaire ebolavirus–Infected Cultures: Preparation, Structural and Biophysical Characterization, and Thermodynamic Stability
1Special Pathogens Branch, Division of Viral and Rickettsial Diseases, National Center for Zoonotic, Vector‐Borne, and Enteric Diseases, and 2Biotechnology Core Facility Branch, Division of Scientific Resources, National Center for Prevention, Detection, and Control of Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia
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 β‐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 (
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°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.
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Potential conflicts of interest: none reported.
Financial support: Centers for Disease Control and Prevention (CDC); Research Participation Program administered by the Oak Ridge Institute for Science and Education through an interagency agreement between the US Department of Energy and the CDC (support to L.G.B. in the Division of Viral and Rickettsial Diseases). Supplement sponsorship is detailed in the Acknowledgments.
The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the funding agency.