+ Resolve Article
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter

+ Translate
+ Subscribe to Site Feed
GeoScience Most Shared ContentMost Shared Content

IgG Fab fragments forming bivalent complexes by a conformational mechanism that is reversible by osmolytes

, : IgG Fab fragments forming bivalent complexes by a conformational mechanism that is reversible by osmolytes. Journal of Biological Chemistry 287(51): 42936-42950

Generated by proteolytic cleavage of immunoglobulin, Fab fragments possess great promise as blocking reagents, able to bind receptors or other targets without inducing cross-linking. However, aggregation of Fab preparations is a common occurrence, which generates intrinsic stimulatory capacity and thwarts signal blockade strategies. Using a panel of biochemical approaches, including size exclusion chromatography, SDS-PAGE, mass spectrometry, and cell stimulation followed by flow cytometry, we have measured the oligomerization and acquisition of stimulatory capacity that occurs in four monoclonal IgG Fabs specific for TCR/CD3. Unexpectedly, we observed that all Fabs spontaneously formed complexes that were precisely bivalent, and these bivalent complexes possessed most of the stimulatory activity of each Fab preparation. Fabs composing bivalent complexes were more susceptible to proteolysis than monovalent Fabs, indicating a difference in conformation between the Fabs involved in these two different states of valency. Because osmolytes represent a class of compounds that stabilize protein folding and conformation, we sought to determine the extent to which the amino acid osmolyte l-proline might impact bivalent Fab complexation. We found that l-proline (i) inhibited the adoption of the conformation associated with bivalent complexation, (ii) preserved Fab monovalency, (iii) reversed the conformation of preformed bivalent Fabs to that of monovalent Fabs, and (iv) separated a significant percentage of preformed bivalent complexes into monovalent species. Thus, Fab fragments can adopt a conformation that is compatible with folding or packing of a bivalent complex in a process that can be inhibited by osmolytes.


PMID: 23109335

DOI: 10.1074/jbc.M112.410217

Other references

Epstein, J., 2000: Hepatitis C virus lookback: emerging science and public policy. Transfusion 40(1): 3-5

Brissette, A.; Strube, Y.N.; Farmer, J.; Kratky, V., 2015: Glucose transporter isoform-1 receptor-positive infantile capillary hemangiomas: case report and literature review. Canadian Journal of Ophthalmology. Journal Canadien D'ophtalmologie 49(6): E156-E158

Gallagher, U.M., 1971: Adoption resources for black children. Children 18(2): 49-53

D.G.acomo, T.; Venuta, F.; Diso, D.; Coloni, G.Furio., 2006: Successful treatment with one-way endobronchial valve of large air-leakage complicating narrow-bore enteral feeding tube malposition. Tracheopulmonary intubation is the most common misplacement site for narrow-bore feeding tube and it might be associated with severe pleuro-pulmonary complications. A 38-year-old female with a severe bilateral pneumonia and acute respiratory insuf...

Dinulos, J.G.H.; Zembowicz, A., 2008: Case records of the Massachusetts General Hospital. Case 32-2008. A 10-year-old girl with recurrent oral lesions and cutaneous bullae. New England Journal of Medicine 359(16): 1718-1724

Sperry, O.E.; Morrow, J., 1952: Quality and quantity of seed from bitterweed killed with herbicides. Prog Rept 1447 Texas Agric Expt Sta : 1-3

Lemma, E.; Constantine, N.T.; Kassa, D.; Messele, T.; Mindaye, T.; Taye, G.; Abebe, A.; Tamene, W.; Tebje, M.; Gebremeskel, W.; Adane, A.; Gezahegn, N., 2010: Human herpesvirus 8 infection in HIV-1-infected and uninfected pregnant women in Ethiopia. Human Herpes Virus (HHV-8) is related to Kaposi Saracoma, an opportunistic infection occurring with HIV infection. Little is known about the seroepidemiology of Human Herpesvirus 8 (HHV-8) infection among Ethiopian women, even though women are a m...

Tanaka, A.; Nonoyama, M.; Hampar, B., 1976: Partial elimination of latent Epstein-Barr virus genomes from virus-producing cells by cyclohexamide. Virology 70(1): 164-170

Sedghi, A.; Rezaei, B., 2016: Effect of background dielectric on TE-polarized photonic bandgap of metallodielectric photonic crystals using Dirichlet-to-Neumann map method. NlmCategory="UNASSIGNED">Using the Dirichlet-to-Neumann map method, we have calculated the photonic band structure of two-dimensional metallodielectric photonic crystals having the square and triangular lattices of circular metal rods...

Niederberger, M., 1976: Therapy of coronary heart disease. Wiener Medizinische Wochenschrift 126(32-35): 469-473