title: The amino acid sequence of the glycosylated amyloid immunoglobulin light chain protein AL MS.
abstract: The authors report on the amino acid sequence of the glycosylated amyloid protein AL MS. The amyloid fibrils were extracted from the spleen of a patient (MS.) with amyloidosis. The protein AL MS was purified from the amyloid fibrils by gel filtration. SDS-PAGE performed on the purified protein material showed glycosylated protein bands in the range of 22 to 32 kDa, corresponding to polymerization of N-terminal fragments. The protein was characterized by amino acid analysis and Edman degradation. Tryptic digest combined with Staphylococcal V8 protease, chymotrypsin and pyroglutamate aminopeptidase digestion, as well as cleavage with BNPS-skatole, established the complete amino acid sequence of 168 residues. The protein was compared to other proteins in the SWISSPROT databank, showing homology with the immunoglobulin light chain variable subgroup lamda I. AL MS showed some unique amino acid substitutions. Highly conserved residues Gly(57) and Arg(61), were exchanged to arginine and glutamine, respectively, possibly altering the three- dimensional structure of the protein.
authors.affiliation: Department of Biochemistry/Biotechnology Centre of Oslo, University of Oslo, Norway.
authors.forename: L A
authors.initials: LA
authors.lastname: Omtvedt
authors.forename: G
authors.initials: G
authors.lastname: Husby
authors.forename: G G
authors.initials: GG
authors.lastname: Cornwell
authors.forename: R A
authors.initials: RA
authors.lastname: Kyle
authors.forename: K
authors.initials: K
authors.lastname: Sletten
mesh_terms: D000595:Amino Acid Sequence; D000682:Amyloid / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification; D000686:Amyloidosis / Q000235:genetics / Q000276:immunology; D006031:Glycosylation; D006801:Humans; D007147:Immunoglobulin Light Chains / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification; D007146:Immunoglobulin lambda-Chains / Q000235:genetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D017354:Point Mutation; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid
chemical_list: D000682:Amyloid; D007147:Immunoglobulin Light Chains; D007146:Immunoglobulin lambda-Chains; C035222:amyloid protein AL