title: The fundamental unit of synthetic melanin: a verification by tunneling microscopy of X-ray scattering results.
abstract: A characteristic dimension of a melanin protomolecule synthesized from tyrosine has been investigated by scanning tunneling microscopy (STM). Identification of a melanin protomolecule of approximately approximately 20 A lateral extent and approximately 10 A height has been established. This size is in good agreement with models constructed to fit wide angle X-ray diffraction experiments on melanin. These protomolecules are believed to consist of Van der Waals interacting stacks of a basic random polymer of 5.6 indolequinone units. There is extensive pi-delocalization within the individual polymeric sheets. Structure minimization and molecular orbital techniques were employed to verify the X-ray and STM results.
authors.affiliation: Amoco Research Center, Amoco Corporation, Naperville, IL 60566-7011.
authors.forename: G W
authors.initials: GW
authors.lastname: Zajac
authors.forename: J M
authors.initials: JM
authors.lastname: Gallas
authors.forename: J
authors.initials: J
authors.lastname: Cheng
authors.forename: M
authors.initials: M
authors.lastname: Eisner
authors.forename: S C
authors.initials: SC
authors.lastname: Moss
authors.forename: A E
authors.initials: AE
authors.lastname: Alvarado-Swaisgood
mesh_terms: D008543:Melanins / Q000737:chemistry*; D016252:Microscopy, Scanning Tunneling; D008958:Models, Molecular; D014961:X-Ray Diffraction
chemical_list: D008543:Melanins