title: The position of the disulfide bonds in human plasma alpha 2 HS-glycoprotein and the repeating double disulfide bonds in the domain structure.
abstract: The positions of the inter- and intra-chain disulfide bonds of human plasma alpha 2 HS-glycoprotein were determined. alpha 2 HS-glycoprotein was digested with acid proteinase and then with thermolysin. The disulfide bonds containing peptides were separated by reversed-phase HPLC and detected by SBD-F (7-fluorobenzo-2-oxa-1,3-diasole-4-sulfonic acid ammonium salt) method. One inter-disulfide bond containing peptide and five intra-disulfide bond containing peptides (A-chain) were purified and identified as Cys-18 (B-chain)--Cys-14 (A-chain), Cys-71--Cys-82, Cys-96--Cys-114, Cys-128--Cys-131, Cys-190--Cys-201 and Cys-212--Cys-229, respectively. The location of the intra-disulfide bonds revealed that the A-chain of alpha 2 HS-glycoprotein is composed of three domains. Two domains were shown to possess intramolecular homology judging from the total chain length of the domains, size of the loops formed by the S--S bonds, the location of two disulfide loops near the C-terminal end of domains A and B, the distance between two S--S bonds of each domain, the amino acid sequence homology between these two domains (22.6%), number of amino acid residues between the second S--S loops and the end of domains A and B, and the positions of the ordered structures.
authors.affiliation: Department of Biochemistry, Boston University School of Medicine, Boston University Medical Center, MA.
authors.forename: T
authors.initials: T
authors.lastname: Araki
authors.forename: Y
authors.initials: Y
authors.lastname: Yoshioka
authors.forename: K
authors.initials: K
authors.lastname: Schmid
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D001798:Blood Proteins / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D003544:Cysteic Acid / Q000032:analysis; D004220:Disulfides / Q000378:metabolism*; D005456:Fluorescent Dyes; D005464:Fluorobenzenes; D006801:Humans; D007704:Kininogens; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000302:isolation & purification; D010447:Peptide Hydrolases / Q000378:metabolism; D011487:Protein Conformation; D012689:Sequence Homology, Nucleic Acid; D013439:Sulfhydryl Reagents; D013820:Thermolysin / Q000378:metabolism; D060749:alpha-2-HS-Glycoprotein
chemical_list: C556354:AHSG protein, human; D000596:Amino Acids; D001798:Blood Proteins; D004220:Disulfides; D005456:Fluorescent Dyes; D005464:Fluorobenzenes; D007704:Kininogens; D010446:Peptide Fragments; D013439:Sulfhydryl Reagents; D060749:alpha-2-HS-Glycoprotein; C037802:7-fluorobenzo-2-oxa-1,3-diazole-4-sulfonate; D003544:Cysteic Acid; D010447:Peptide Hydrolases; D013820:Thermolysin