Large cytoplasmic inclusion body kappa-chain has unusual intrachain disulfide bonding.
The Ig kappa L chain synthesized by the mouse hybridoma line F10 forms large fibrils in the lumen of the endoplasmic reticulum. Despite the formation of these inclusion bodies, free kappa-chain is secreted. Both intracellular and secreted kappa-chains in this line migrate faster on SDS gels; thus, the F10 kappa-chain seems to be more compact than normal Ig L chain. In normal kappa-chain, four cysteine residues form intrachain disulfide bonds and the fifth connects the L chain to the H chain. Although the five cysteine residues of the aberrant kappa-chain are in the normal positions, they display an unusual gel pattern when the intrachain disulfide bonds are opened with 2-ME; that is, the intrachain disulfide bonding pattern of F10 kappa-chain seems to be unusual. It is suggested that the abnormal folding pattern favors fibril formation.
Department of Microbiology and Immunology, University of California, San Francisco 94143-0414.
H M
HM
Jäck
B
B
Sloan
G
G
Grisham
D
D
Reason
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M
Wabl
D000595:Amino Acid Sequence; D000686:Amyloidosis / Q000276:immunology; D000818:Animals; D001483:Base Sequence; D003460:Crystallization; D003593:Cytoplasm / Q000276:immunology / Q000378:metabolism; D004220:Disulfides / Q000737:chemistry; D006825:Hybridomas / Q000276:immunology; D007145:Immunoglobulin kappa-Chains / Q000096:biosynthesis / Q000737:chemistry* / Q000648:ultrastructure; D002479:Inclusion Bodies / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017510:Protein Folding
D004220:Disulfides; D007145:Immunoglobulin kappa-Chains