Protein-Engineering Improvement of Direct Electron Transfer-Type Bioelectrocatalytic Properties of d-Fructose Dehydrogenase
Protein-Engineering Improvement of Direct Electron Transfer-Type Bioelectrocatalytic Properties of d-Fructose Dehydrogenase
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DOI：
10.5796/electrochemistry.18-00068
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发表时间：
2019-01
期刊：
影响因子：
2.5
通讯作者：
Yuya Hibino;S. Kawai;Y. Kitazumi;O. Shirai;K. Kano
中科院分区：
文献类型：
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作者：
Yuya Hibino;S. Kawai;Y. Kitazumi;O. Shirai;K. Kano
D-果糖脱氢酶（FDH）在亚基I中含有黄素腺嘌呤二核苷酸（FAD）和三个血红素C部分（从N-末端起的1c、2c和3c）作为电子传递中继位点。在直接电子转移型生物电催化FDH的过程中，电子转移是从FAD，通过血红素3c，到血红素2c，而不通过血红素1c。为了提高其生物电催化性能，我们构建了一个突变体（M450 Q Δ1cFDH），该突变体去除了血红素1c的143个氨基酸残基，并将血红素2c的第六轴配体M450替换为谷氨酰胺，使血红素2c的形式电位负移。将M450 Q Δ1cFDH变体吸附在平面金电极上。在循环伏安法中，该电极对果糖氧化产生一个明显的S形稳态催化波。极限电流密度是1.4倍以上的重组（天然）FDH。波的半波电位向负方向移动0.2V。M450 Q Δ1cFDH在适合于DET型生物电催化的方向上相当均匀地吸附。©日本电化学学会版权所有。
D-Fructose dehydrogenase (FDH) contains a flavin adenine dinucleotide (FAD) in subunit I and three heme c moieties (1c, 2c, and 3c from the N-terminus) as the electron transfer relaying sites. The electron transfer in direct electron transfer-type bioelectrocatalysis of FDH is proposed to proceed in sequence from FAD, through heme 3c, to heme 2c without going through heme 1c. In order to improve the performance of the bioelectrocatalysis, we constructed a variant (M450QΔ1cFDH) in which 143 amino acid residues involving heme 1c were removed and M450 as the sixth axial ligand of heme 2c was replaced with glutamine to negatively shift the formal potential of heme 2c. The M450QΔ1cFDH variant was adsorbed on a planar gold electrode. The variant-adsorbed electrode produced a clear sigmoidal steady-state catalytic wave of fructose oxidation in cyclic voltammetry. The limiting current density was 1.4 times larger than that of the recombinant (native) FDH. The half-wave potential of the wave shifted by 0.2V to the negative direction. M450QΔ1cFDH adsorbed rather homogeneously in orientations suitable for DET-type bioelectrocatalysis. © The Electrochemical Society of Japan, All rights reserved.