α-Helical Polypeptide Films Grown From Sulfide or Thiol Linkers on Gold Surfaces
摘要:
We prepared two new linkers, S-functionalized adamantane derivatives 2 and 3, which bind as monolayers on polycrystalline gold. From these surface anchors, both L- and D-isomers of alanine can be grown as thin films of a-helical polypeptides directed from the gold surface by using the appropriate N-carboxyalanine anhydride. FT-IR Studies show that these layers are roughly 1000-Angstrom thick and that, under the same growth conditions. the L-polypeptide layers grow at a rate ca. 30% greater than that of the non-natural D-amino acid. X-Ray photoelectron spectroscopy studies shove that, upon equilibration, all three S-atoms of the sulfide moieties of 2 are bound to the gold surface, and that, on average, three of the four thiols of 3 are chemoadsorbed. The essential role of H2O on the surface of these films as a necessary component in these gas-phase polymerization reactions is demonstrated.