title: Functionalization of a protein surface with per-O-methylated β-cyclodextrin.
abstract: Per-O-methylated β-cyclodextrin (CD) bearing an iodoacetamide group at the 6-position was synthesized to functionalize protein surfaces. Bovine serum albumin (BSA) was quantitatively modified with the CD derivative by the S(N) 2 reaction of iodoacetamide with a cysteine residue (Cys34) on the BSA surface. The resultant CD-functionalized BSA (BSA-CD) spontaneously dimerized upon addition of an anionic tetraarylporphyrin (TPPS) through the supramolecular 1:2 complexation between TPPS and CD on the protein surface. The BSA-CD/TPPS complex further complexed with ferric protoporphyrin IX (hemin) in the hydrophobic pockets of albumin to form a hemin/BSA-CD/TPPS ternary complex in which static fluorescence quenching occurred owing to intramolecular electron transfer from the photoexcited TPPS to hemin.
authors.affiliation: Department of Molecular Chemistry and Biochemistry, Doshisha University, Kyotanabe, Kyoto, Japan. hkitagis@mail.doshisha.ac.jp
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kitagishi
authors.forename: Kazuya
authors.initials: K
authors.lastname: Kashiwa
authors.forename: Koji
authors.initials: K
authors.lastname: Kano
mesh_terms: D000818:Animals; D002417:Cattle; D006427:Hemin / Q000737:chemistry / Q000378:metabolism; D057927:Hydrophobic and Hydrophilic Interactions / Q000187:drug effects; D008697:Methane / Q000031:analogs & derivatives / Q000737:chemistry; D008954:Models, Biological; D058105:Polymerization / Q000187:drug effects; D011166:Porphyrins / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D011485:Protein Binding / Q000187:drug effects; D055550:Protein Stability / Q000187:drug effects*; D012710:Serum Albumin, Bovine / Q000737:chemistry / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D013057:Spectrum Analysis; D013499:Surface Properties / Q000187:drug effects; D047392:beta-Cyclodextrins / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D011166:Porphyrins; D047392:beta-Cyclodextrins; C051224:methyl radical; D012710:Serum Albumin, Bovine; C016136:tetraphenylporphine sulfonate; D006427:Hemin; D008697:Methane