title: [A comparative structural analysis of Fab-fragments of monoclonal rheumatoid and non-rheumatoid immunoglobulins M].
abstract: The spin-labeling method was used to study the Fab- and Fab-RF-fragments of IgM and IgM-RF, respectively. The spin-label 2,2,6,6-tetramethyl-4-dichloro-sym-triazinyl-aminopiperidine-1-oxyl was introduced into the peptide moiety of the proteins. The rotational correlation time t of the spin-label carrier was determined based on the temperature-viscosity dependence of the EPR spectra parameters of the spin-labeled proteins. The tau values for Fab- and Fab-RF-fragments were 21 +/- 2 and 12 +/- 1 ns, respectively. The data strongly suggest that the significantly lower tau value for the Fab-RF-fragment may be due to the local structural flexibility of the fragment, which in turn may explain the peculiarities of IgM-RF as an autoantibody.
authors.forename: V P
authors.initials: VP
authors.lastname: Timofeev
authors.forename: Ia V
authors.initials: IaV
authors.lastname: Tkachev
authors.forename: V V
authors.initials: VV
authors.lastname: Novikov
authors.forename: E Iu
authors.initials: EIu
authors.lastname: Varlamova
authors.forename: V A
authors.initials: VA
authors.lastname: Lapuk
mesh_terms: D004578:Electron Spin Resonance Spectroscopy; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000737:chemistry*; D007075:Immunoglobulin M / Q000737:chemistry*; D012217:Rheumatoid Factor / Q000737:chemistry*
chemical_list: D007140:Immunoglobulin Fab Fragments; D007075:Immunoglobulin M; D012217:Rheumatoid Factor