The cysteine residues in the carboxy terminal domain of tropoelastin form an intrachain disulfide bond that stabilizes a loop structure and positively charged pocket.
Analysis of purified bovine tropoelastin with Ellman's reagent and [14C]iodoacetamide demonstrated that the only two cysteine residues in the molecule form an intrachain disulfide bond. Molecular modeling suggests that the cysteine residues are juxtaposed as the result of a tight turn that produces an antiparallel beta structure. Protruding from the C-terminal end of the turn is the sequence Arg-Lys-Arg-Lys which forms the floor of a positively charged pocket created by the extension of the arginine and lysine side chains on opposite sides of the peptide chain perpendicular to the plane of the turn. The side chain of a conserved lysine residue in the disulfide-bonded loop forms the top of the pocket. This positively charged pocket may define a binding site for acidic microfibrillar proteins that mediate elastic fiber assembly.
Brown
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Department of Cell Biology, Jewish Hospital, Washington University Medical Center, St. Louis, MO 63110.
Mecham
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Tisdale
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Mecham
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D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D003545:Cysteine; D004220:Disulfides; D004228:Dithionitrobenzoic Acid; D004355:Drug Stability; D004549:Elastin / Q000737:chemistry / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D007460:Iodoacetamide / Q000378:metabolism; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry; D011487:Protein Conformation; D012689:Sequence Homology, Nucleic Acid; D014333:Tropoelastin / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
D004220:Disulfides; D010446:Peptide Fragments; D014333:Tropoelastin; D004549:Elastin; D004228:Dithionitrobenzoic Acid; D003545:Cysteine; D007460:Iodoacetamide