title: Synthesis and conformation of the trimeric coiled-coil segment of laminin.
abstract: A disulfide linked 95-mer parallel hetero-trimeric active site segment of laminin was designed and synthesised. The three subunits, A (32-mer), B1 (30-mer) and B2 (33-mer), were prepared by Boc-based solid-phase peptide synthesis involving a two-step trimethylsilyl bromide-thioanisole and HF deprotection procedure. The interlinking of the three subunits was accomplished by the stepwise selective formation of two disulfide bridges using air-oxidation and thallium (III) trifluoroacetate oxidation. The conformations of the synthetic peptides were studied by circular dichroism (CD) spectroscopy, showing that the hetero-dimer, B1-B2, one of the homo-dimers, B1-B1, and the trimer are 30 to 40% in the alpha-helical conformation in aqueous buffer. Variable temperature CD studies demonstrated that the trimer is considerably more stable (melting temperature (Tm) = 61 degrees) than the hetero-dimer, B1-B2 (Tm = 36 degrees).
authors.affiliation: Laboratory of Medicinal Chemistry, DTP, DCT, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892.
authors.forename: M
authors.initials: M
authors.lastname: Nomizu
authors.forename: A
authors.initials: A
authors.lastname: Utani
authors.forename: N
authors.initials: N
authors.lastname: Shiraishi
authors.forename: Y
authors.initials: Y
authors.lastname: Yamada
authors.forename: P P
authors.initials: PP
authors.lastname: Roller
mesh_terms: D000595:Amino Acid Sequence; D004220:Disulfides / Q000737:chemistry; D007797:Laminin / Q000138:chemical synthesis* / Q000737:chemistry; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017433:Protein Structure, Secondary
chemical_list: D004220:Disulfides; D007797:Laminin; D046911:Macromolecular Substances