A GFET nitrile sensor using a graphene-binding fusion protein

Abubaker Abdillahi Mohamed, Hironaga Noguchi, Mirano Tsukiiwa, Chen Chen, Rachel Heath, Muhammad Qadri Effendy Bin Mubarak, Takumi Komikawa, Masayoshi Tanaka, Mina Okochi, Samuel De Visser, Yuhei Hayamizu, Christopher F. Blanford

Research output: Contribution to journalArticlepeer-review


A new route to single-step, non-covalent immobilization of proteins on graphene is exemplified with the first biosensor for nitriles based on a graphene field-effect transistor (GFET). The biological recognition element is a fusion protein consisting of nitrile reductase QueF from E. coli with an N-terminal self-assembling and graphene-binding dodecapeptide. Atomic force microscopy and analysis using a quartz crystal microbalance show that both the oligopeptide and the fusion protein incorporating it form a single adlayer of monomeric enzyme on graphene. The fusion protein has a 6.3-fold increase in binding affinity for benzyl cyanide (BnCN) versus wild-type QueF and a 1.4-fold increase for affinity for the enzyme’s natural substrate preQ0. Density functional theory analysis of QueF’s catalytic cycle with BnCN shows similar transition-state barriers to preQ0, but differences in the formation of the initial thioimidate covalent bond (ΔG‡ = 19.0 kcal mol–1 for preQ0 vs 27.7 kcal mol–1 for BnCN) and final disassociation step (ΔG = –24.3 kcal mol–1 for preQ0 vs ΔG = +4.6 kcal mol–1 for BnCN). Not only do these results offer a single-step route to GFET modification, but they also present new opportunities in the biocatalytic synthesis of primary amines from nitriles.
Original languageEnglish
JournalAdvanced Functional Materials
Publication statusAccepted/In press - 22 Aug 2022


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