title: Reconstructing a flavodoxin oxidoreductase with early amino acids.
abstract: Primitive proteins are proposed to have utilized organic cofactors more frequently than transition metals in redox reactions. Thus, an experimental validation on whether a protein constituted solely by early amino acids and an organic cofactor can perform electron transfer activity is an urgent challenge. In this paper, by substituting "late amino acids (C, F, M, T, W, and Y)" with "early amino acids (A, L, and V)" in a flavodoxin, we constructed a flavodoxin mutant and evaluated its characteristic properties. The major results showed that: (1) The flavodoxin mutant has structural characteristics similar to wild-type protein; (2) Although the semiquinone and hydroquinone flavodoxin mutants possess lower stability than the corresponding form of wild-type flavodoxin, the redox potential of double electron reduction Em,7 (fld) reached -360 mV, indicating that the flavodoxin mutant constituted solely by early amino acids can exert effective electron transfer activity.
authors.affiliation: School of Life Sciences, Shandong Normal University, Jinan 250014, China. lumingfeng4659@sina.com.cn.
authors.forename: Ming-Feng
authors.initials: MF
authors.lastname: Lu
authors.forename: Hong-Fang
authors.initials: HF
authors.lastname: Ji
authors.forename: Ting-Xuan
authors.initials: TX
authors.lastname: Li
authors.forename: Shou-Kai
authors.initials: SK
authors.lastname: Kang
authors.forename: Yue-Jie
authors.initials: YJ
authors.lastname: Zhang
authors.forename: Jue-Fei
authors.initials: JF
authors.lastname: Zheng
authors.forename: Tian
authors.initials: T
authors.lastname: Tian
authors.forename: Xi-Shuai
authors.initials: XS
authors.lastname: Jia
authors.forename: Xing-Ming
authors.initials: XM
authors.lastname: Lin
authors.forename: Hong-Yu
authors.initials: HY
authors.lastname: Zhang
mesh_terms: D000596:Amino Acids / Q000378:metabolism*; D002942:Circular Dichroism; D005453:Fluorescence; D007700:Kinetics; D045851:Megasphaera / Q000201:enzymology*; D016296:Mutagenesis / Q000235:genetics*; D050505:Mutant Proteins / Q000302:isolation & purification / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D009247:NADH, NADPH Oxidoreductases / Q000302:isolation & purification / Q000378:metabolism*; D010084:Oxidation-Reduction; D011994:Recombinant Proteins / Q000302:isolation & purification
chemical_list: D000596:Amino Acids; D050505:Mutant Proteins; D011994:Recombinant Proteins; D009247:NADH, NADPH Oxidoreductases; C116041:flavodoxin NADPH oxidoreductase