Scanning Force Microscopy Images of Cytochrome c Oxidase Immobilized in an Electrode-Supported Lipid Bilayer Membrane

Abstract

Scanning force microscopic images of cytochrome c oxidase immobilized within an electrode-supported lipid bilayer membrane are reported. These images represent the first direct evidence that the microscopic architecture of this important model system effectively mimics the microstructure proposed for the inner mitochondrial membrane. The images reveal (1) that the oxidase is present as monomers and small aggregates within the supported membrane and (2) that the oxidase constitutes ∼20% of the lipid bilayer membrane. The latter finding allows an estimation of the lower limit for the minimum turnover rate (∼0.5 electrons/s) required for the transition of the oxidase from its resting to pulsed kinetic state.

d-Fructose detection based on the direct heterogeneous electron transfer reaction of fructose dehydrogenase adsorbed onto multi-walled carbon nanotubes synthesized on platinum electrode

“…Recently, direct heterogeneous electron transfer reactions between enzymes and electrodes have also been reported. Direct electron transfer reactions on electrodes were achieved for heme-containing enzymes such as cytochrome oxidases (Cullison et al, 1994;Burgess et al, 1998), cellobiose dehydrogenase (Gorton et al, 1999;Lindgren et al, 2001;Stoica et al, 2005Stoica et al, , 2006Harreither et al, 2007), theophylline oxidase (Christenson et al, 2004), alcohol dehydrogenase (Gorton et al, 1999;Ikeda et al, 1993;Ramanavicius et al, 1999;Razumiene et al, 2001), sulfite oxidase (Ferapontova et al, 2003) and peroxidase (Gorton et al, 1999;Ferapontova et al, 2001;Andreu et al, 2007), as well as for multicopper enzymes such as laccase (Gorton et al, 1999;Shleev et al, 2005b;Gupta et al, 2004;Pita et al, 2006), ascorbate oxidase (Gorton et al, 1999 Shleev et al, 2005b), bilirubin oxidase (Shleev et al, 2004(Shleev et al, , 2005aTsujimura et al, 2004Tsujimura et al, , 2005Zheng et al, 2006;Tominaga et al, 2006), ceruloplasmin (Shleev et al, 2005b) and Cu efflux oxidase (Miura et al, 2007). It was also reported that the direct electron transfer reactions of glucose oxidase at highly oriented pyrolytic graphite and at carbon nanotubes (Patolsky et al, 2004;Gong et al, 2005;Wang, 2005;Gooding, 2005;Ivnitski et al, 2006;…”

Characterization of cyanide binding to cytochrome c oxidase immobilized in electrode-supported lipid bilayer membranes

“…From the phase contrast tapping mode atomic force microscopy data reported previously by this group [35], the surface coverage of CcO on the modified electrode was estimated to be approximately 20%. The diameter of the beef CcO is approximately 80 Å based on its crystal structure [58,59], which yields 8.0 · 10 10 CcO molecules on the surface of the modified electrode (geometric area of 0.2 cm 2 ).…”

“…Phase contrast tapping-mode scanning force microscopy (TM-SFM) has confirmed that the electrode architecture mimics the native membrane structure of the oxidase [35], i.e., with the large hydrophilic portion of the enzyme protruding from the bilayer as illustrated in cartoon-fashion in (Fig. 1).…”

Effect of phase transition on the electrochemical behavior of ferredoxin embedded in an artificial lipid membrane film

“…Biological and synthetic lipid membranes have also been used as potential materials [7]. The electrochemical behavior of proteins and enzymes in lipid films has been studied previously [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25]. The quasi-reversible electron transfer reactions of myoglobin embedded in cast films of lipids, cationic and anionic type lipids, and biological and synthetic lipids, on a graphite electrode surface have been examined [12][13][14][15].…”