Forskning ved Københavns Universitet - Københavns Universitet


Spectroscopic properties of light-chain derivatives of murine MOPC-315 immunoglobulin A

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  • R Zidovetzki
  • O Farver
  • I Pecht

Three light-chain derivatives of the homogeneous IgA, secreted by the mouse myeloma MOPC-315, were studied employing circular dichroism and thermal-perturbation spectroscopy: (a) the light-chain dimer with intact native inter-chain disulfide bond, L2,cov; (b) the light-chain dimer with this bond reduced and alkylated, L2,ncov; and (c) the dimer of only the variable regions of the light chains, (VL)2. Comparison of the well resolved circular dichroism spectra of these derivatives allowed the assignments of the bands above 290 nm to the following chromophores: Trp-35L and Trp-91L in the variable domains, and Trp-148L, Trp-185L and the disulfide of Cys-214L in the constant domains. The differences in the spectral characteristics of L2,cov as compared to those of L2,ncov and (VL)2 illustrate the significant influence of the disulfide bridge on the conformation of the L2,cov. Pronounced differences are found between these light-chain derivatives ant the light chain--heavy chain associates, namely the intact protein M-315 and FV fragment. The comparison between the CD spectra of the free and the hapten-bound L2,cov, L2,ncov and (VL)2 directly demonstrates the existence of the conformational transitions in these proteins induced by hapten binding.

TidsskriftEuropean Journal of Biochemistry
Udgave nummer1
Sider (fra-til)97-100
Antal sider4
StatusUdgivet - 1981

ID: 113627149