title: Doping human serum albumin with retinoate markedly enhances electron transport across the protein.
abstract: Electrons can migrate via proteins over distances that are considered long for nonconjugated systems. The nanoscale dimensions of proteins and their enormous structural and chemical flexibility makes them fascinating subjects for exploring their electron transport (ETp) capacity. One particularly attractive direction is that of tuning their ETp efficiency by "doping" them with small molecules. Here we report that binding of retinoate (RA) to human serum albumin (HSA) increases the solid-state electronic conductance of a monolayer of the protein by >2 orders of magnitude for RA/HSA ≥ 3. Temperature-dependent ETp measurements show the following with increasing RA/HSA: (a) The temperature-independent current magnitude of the low-temperature (<190 K) regime increases significantly (>300-fold), suggesting a decrease in the distance-decay constant of the process. (b) The activation energy of the thermally activated regime (>190 K) decreases from 220 meV (RA/HSA = 0) to 70 meV (RA/HSA ≥ 3).
authors.affiliation: Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Nadav
authors.initials: N
authors.lastname: Amdursky
authors.forename: Israel
authors.initials: I
authors.lastname: Pecht
authors.forename: Mordechai
authors.initials: M
authors.lastname: Sheves
authors.forename: David
authors.initials: D
authors.lastname: Cahen
mesh_terms: D004553:Electric Conductivity; D004579:Electron Transport; D004583:Electrons; D006801:Humans; D008958:Models, Molecular; D011485:Protein Binding; D012709:Serum Albumin / Q000737:chemistry* / Q000378:metabolism; D014212:Tretinoin / Q000031:analogs & derivatives* / Q000378:metabolism
chemical_list: D012709:Serum Albumin; D014212:Tretinoin