title: Faster interprotein electron transfer in a [myoglobin, b⁵] complex with a redesigned interface.
abstract: Direct measurements of electron transfer (ET) within a protein-protein complex with a redesigned interface formed by physiological partner proteins myoglobin (Mb) and cytochrome b(5) (b(5)) reveal interprotein ET rates comparable to those observed within the photosynthetic reaction center. Brownian dynamics simulations show that Mb in which three surface acid residues are mutated to lysine binds b(5) in an ensemble of configurations distributed around a reactive most-probable structure. Correspondingly, charge-separation ET from a photoexcited singlet zinc porphyrin incorporated within Mb to the heme of b(5) and the follow-up charge-recombination exhibit distributed kinetics, with median rate constants, k(f)(s) = 2.1 × 10(9) second(-1) and k(b)(s) = 4.3 × 10(10) second(-1), respectively. The latter approaches that for the initial step in photosynthetic charge separation, k = 3.3 × 10(11) second(-1).
authors.affiliation: Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3113, USA.
authors.forename: Peng
authors.initials: P
authors.lastname: Xiong
authors.forename: Judith M
authors.initials: JM
authors.lastname: Nocek
authors.forename: Josh
authors.initials: J
authors.lastname: Vura-Weis
authors.forename: Jenny V
authors.initials: JV
authors.lastname: Lockard
authors.forename: Michael R
authors.initials: MR
authors.lastname: Wasielewski
authors.forename: Brian M
authors.initials: BM
authors.lastname: Hoffman
mesh_terms: D000818:Animals; D002417:Cattle; D015786:Cytochromes b5 / Q000737:chemistry*; D004583:Electrons; D006736:Horses; D046912:Multiprotein Complexes / Q000737:chemistry; D009211:Myoglobin / Q000737:chemistry*; D010788:Photosynthesis; D013995:Time
chemical_list: D046912:Multiprotein Complexes; D009211:Myoglobin; D015786:Cytochromes b5