title: Molecular simulation of flavin adenine dinucleotide immobilized on charged single-walled carbon nanotubes for biosensor applications.
abstract: The reconstitution of apo-glucose oxidase (apo-GOx) on single-walled carbon nanotubes (SWNTs) functionalized with the cofactor, flavin adenine dinucleotide (FAD), greatly improved electron transfer turnover rate of the redox reactions in glucose sensing with glucose sensors. The research reported here is aimed to better understand molecular details of affection of the charging SWNT to the conformational changes of FAD, in order to find a rational design and selection scheme of SWNT which is suitable for the FAD and apo-GOx to perform their reconstitution. In this report, molecular simulations of FAD functionalized differently charged SWNTs were carried outin an aqueous environment, with counterions to maintain total charge neutrality. The conformation and orientation changes were observed by both trajectory and quantitative analyses. The simulation results showed that in both uncharged and positively charged SWNT situations, FAD adsorbed onto SWNT at the end of the simulations, which increased the steric resistance of molecules and hindered the reconstitution of apo-GOx and FAD to some degree. By contrast, FAD functionalized negatively charged SWNT maintained its original conformation largely. In addition, negatively charged SWNT may be the best choice for electron transfer mediator for the reconstitution of apo-GOx on relay-cofactor units associated with electrodes.
authors.affiliation: College of Biomedical Engineering & Instrument Science, Zhejiang University, PR China.
authors.forename: Guang
authors.initials: G
authors.lastname: Yang
authors.forename: Zhengzhong
authors.initials: Z
authors.lastname: Kang
authors.forename: Xuesong
authors.initials: X
authors.lastname: Ye
authors.forename: Tao
authors.initials: T
authors.lastname: Wu
authors.forename: Qin
authors.initials: Q
authors.lastname: Zhu
mesh_terms: D001234:Aspergillus niger / Q000737:chemistry / Q000201:enzymology*; D015374:Biosensing Techniques; D004579:Electron Transport; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism*; D005182:Flavin-Adenine Dinucleotide / Q000737:chemistry / Q000378:metabolism*; D005947:Glucose / Q000032:analysis; D005949:Glucose Oxidase / Q000737:chemistry / Q000378:metabolism*; D008968:Molecular Conformation; D056004:Molecular Dynamics Simulation; D037742:Nanotubes, Carbon / Q000737:chemistry*
chemical_list: D004800:Enzymes, Immobilized; D037742:Nanotubes, Carbon; D005182:Flavin-Adenine Dinucleotide; D005949:Glucose Oxidase; D005947:Glucose