A transient expansion of the native state precedes aggregation of recombinant human interferon-γ

• DOI: 10.1073/pnas.95.24.14142
• Publication Date: 2002-07-26T14:42:40Z
• Authors: Brent S. Kendrick; John F. Carpenter; Jeffrey L. Cleland; Theodore W. Randolph
• Keywords: Guanidine

Aggregation of proteins, even under conditions favoring the native state, is a ubiquitous problem in biotechnology and biomedical engineering. Providing mechanistic basis for pathways that lead to aggregation should allow development rational approaches its prevention. We have chosen recombinant human interferon-γ (rhIFN-γ) as model protein study aggregation. In presence 0.9 M guanidinium hydrochloride, rhIFN-γ aggregates with first order kinetics, process inhibited by addition sucrose. describe pathway accounts both observed first-order effect this pathway, proceeds through transient expansion state. Sucrose shifts equilibrium within ensemble conformations favor most compact species over more expanded ones, thus stabilizing against This phenomenon attributed preferential exclusion sucrose from surface. addition, kinetic analysis combined solution thermodynamics shows only small (9%) surface area needed form state precedes The used here link kinetics provide powerful tool understanding use excipients inhibit process.