title: Comparative signature diagrams to evaluate biophysical data for differences in protein structure across various formulations.
abstract: A solution to the problem of being able to show statistically significant differences in the measurements of various levels of higher-order protein structure has been an elusive one. We propose the use of comparative signature diagrams (CSDs) to this end. CSDs compare datasets from different biophysical techniques that fingerprint the secondary, tertiary, and quaternary structures of a protein molecule and display statistically significant differences in these datasets. In this paper, we explore the differences in the structures of two proteins (Granulocyte Colony Stimulating Factor [GCSF] and a monoclonal antibody [mAb]) in various formulations. These proteins were chosen based on the extent of differences in structure observed in the formulations. As an initial test, we utilize data from circular dichroism, 8-anilino-1-naphthalene-sulfonate and intrinsic fluorescence spectroscopy, and static light scattering measurements to fingerprint protein structure in the different formulations. Several layers of statistics were explored to visualize the regions of significant differences in the protein spectra. This approach provides a rapid, high-resolution methodology to compare various structural levels of proteins using standard biophysical instrumentation.
authors.affiliation: Bioengineering Graduate Program, University of Kansas, Lawrence, Kansas 66045, USA.
authors.forename: Vidyashankara
authors.initials: V
authors.lastname: Iyer
authors.forename: Nathan
authors.initials: N
authors.lastname: Maddux
authors.forename: Lei
authors.initials: L
authors.lastname: Hu
authors.forename: Weiqiang
authors.initials: W
authors.lastname: Cheng
authors.forename: Ahmed K
authors.initials: AK
authors.lastname: Youssef
authors.forename: Gerhard
authors.initials: G
authors.lastname: Winter
authors.forename: Sangeeta B
authors.initials: SB
authors.lastname: Joshi
authors.forename: David B
authors.initials: DB
authors.lastname: Volkin
authors.forename: C Russell
authors.initials: CR
authors.lastname: Middaugh
mesh_terms: D000911:Antibodies, Monoclonal / Q000737:chemistry*; D059451:Biosimilar Pharmaceuticals / Q000737:chemistry*; D002626:Chemistry, Pharmaceutical; D002942:Circular Dichroism; D030562:Databases, Protein; D016179:Granulocyte Colony-Stimulating Factor / Q000737:chemistry*; D008027:Light; D015233:Models, Statistical; D011489:Protein Denaturation; D055550:Protein Stability; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D012542:Scattering, Radiation; D013050:Spectrometry, Fluorescence; D013696:Temperature
chemical_list: D000911:Antibodies, Monoclonal; D059451:Biosimilar Pharmaceuticals; D016179:Granulocyte Colony-Stimulating Factor