title: Conformation of glutathione adduct and oxidized forms of platelet-derived growth factor.
abstract: The conformational properties of several platelet-derived growth factors (PDGFs) were characterized by circular dichroism (CD), Fourier transform infrared spectroscopy (FTIR), gel filtration and sedimentation equilibrium. Three different forms of disulfide linked dimer, PDGF-AA, PDGF-AB, and PDGF-BB, showed similar far UV CD spectra with evidence for slight beta-structure, but little evidence of other regular secondary structures. These spectra were, however, different from the far UV CD spectra of the glutathione adducts of PDGF-A and B, suggesting that the latter two proteins adopt different conformations in the absence of intra- or inter-molecular disulfide bonds. FTIR studies confirmed this by showing that the glutathione adducts of the PDGF-B protein have a significantly lower amount of regular secondary structures than PDGF-BB. Additionally, the increased bandwidths of the amide I components of the FTIR spectrum of the glutathione adduct indicates a more flexible structure relative to the dimeric form. Sedimentation equilibrium analysis showed that PDGF-BB is primarily a dimer and that the glutathione form is primarily a monomer. Thus, it was concluded that the glutathione derivative has little affinity to form non-covalent dimers in neutral solution.
authors.affiliation: Amgen Inc., Thousand Oaks, CA.
authors.forename: L O
authors.initials: LO
authors.lastname: Narhi
authors.forename: W C
authors.initials: WC
authors.lastname: Kenney
authors.forename: S J
authors.initials: SJ
authors.lastname: Prestrelski
authors.forename: T
authors.initials: T
authors.lastname: Arakawa
authors.forename: D
authors.initials: D
authors.lastname: Lyons
authors.forename: J
authors.initials: J
authors.lastname: Lary
authors.forename: D A
authors.initials: DA
authors.lastname: Yphantis
mesh_terms: D002850:Chromatography, Gel; D002942:Circular Dichroism; D005978:Glutathione / Q000737:chemistry*; D010084:Oxidation-Reduction; D010982:Platelet-Derived Growth Factor / Q000737:chemistry*; D011487:Protein Conformation; D013056:Spectrophotometry, Ultraviolet; D014461:Ultracentrifugation
chemical_list: D010982:Platelet-Derived Growth Factor; D005978:Glutathione