Molecular Monolayers and Interfacial Electron Transfer of<i>Pseudomonas aeruginosa</i>Azurin on Au(111)

Chi, Qijin; Zhang, Jingdong; Nielsen, Jens Frederik Dalsgaard; Friis, Esben P.; Chorkendorff, Ib; Canters, G.W.; Andersen, Jens Enevold Thaulov; Ulstrup, Jens

doi:10.1021/ja993174t

Cited by 256 publications

(319 citation statements)

References 49 publications

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“…All electrochemical potentials are reported versus SCE in this work. Experimental procedures for the pretreatment of Au(111) electrodes and single-crystal electrochemical measurements were similar to those used in our previous reports 47,48 .…”

Section: Methodsmentioning

confidence: 99%

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Direct measurement and modulation of single-molecule coordinative bonding forces in a transition metal complex

et al. 2013

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Coordination chemistry has been a consistently active branch of chemistry since Werner's seminal theory of coordination compounds inaugurated in 1893, with the central focus on transition metal complexes. However, control and measurement of metal-ligand interactions at the single-molecule level remain a daunting challenge. Here we demonstrate an interdisciplinary and systematic approach that enables measurement and modulation of the coordinative bonding forces in a transition metal complex. Terpyridine is derived with a thiol linker, facilitating covalent attachment of this ligand on both gold substrate surfaces and gold-coated atomic force microscopy tips. The coordination and bond breaking between terpyridine and osmium are followed in situ by electrochemically controlled atomic force microscopy at the single-molecule level. The redox state of the central metal atom is found to have a significant impact on the metal-ligand interactions. The present approach represents a major advancement in unravelling the nature of metal-ligand interactions and could have broad implications in coordination chemistry.

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Section: Methodsmentioning

confidence: 99%

“…STM samples were prepared as described above. The detail of experimental procedures on the pretreatment of single-crystal Au(111) substrates and STM imaging can be further referred to our previous reports 47,48 .…”

Section: Methodsmentioning

confidence: 99%

Direct measurement and modulation of single-molecule coordinative bonding forces in a transition metal complex

et al. 2013

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“…Azurin from P. aeruginosa was purified, and its concentration was determined by UV-visible spectrometry as described in ref. 36 Electrochemical Measurements. All measurements were carried out by using an Autolab system (Eco Chemie, Utrecht, The Netherlands) controlled by the general purpose electrochemical system software at room temperature (22 Ϯ 2°C).…”

Section: Methodsmentioning

confidence: 99%

“…Two structural features (a surface disulfide Cys 3 Cys 26 group and a hydrophobic patch around the copper center located at the two opposite ends) can be exploited to confine azurin molecules on Au(111) surfaces with well controlled orientations. Direct self-assembly through the disulfide group orients the protein molecules with the copper center opposite to the electrode surface, with a 26-Å distance between the copper center and the electrode surface (35,36). An interfacial ET rate constant of Ϸ30 s Ϫ1 was observed, largely consistent with intramolecular ET between the copper center and the Cys 3 Cys 26 site measured by pulse radiolysis in homogeneous solution (44 s Ϫ1 ) (29).…”

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confidence: 99%

Long-range protein electron transfer observed at the single-molecule level: In situ mapping of redox-gated tunneling resonance

Chi

Farver

Ulstrup

2005

Proc. Natl. Acad. Sci. U.S.A.

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A biomimetic long-range electron transfer (ET) system consisting of the blue copper protein azurin, a tunneling barrier bridge, and a gold single-crystal electrode was designed on the basis of molecular wiring self-assembly principles. This system is sufficiently stable and sensitive in a quasi-biological environment, suitable for detailed observations of long-range protein interfacial ET at the nanoscale and single-molecule levels. Because azurin is located at clearly identifiable fixed sites in well controlled orientation, the ET configuration parallels biological ET. The ET is nonadiabatic, and the rate constants display tunneling features with distance-decay factors of 0.83 and 0.91 Å ؊1 in H2O and D2O, respectively. Redoxgated tunneling resonance is observed in situ at the single-molecule level by using electrochemical scanning tunneling microscopy, exhibiting an asymmetric dependence on the redox potential. Maximum resonance appears around the equilibrium redox potential of azurin with an on͞off current ratio of Ϸ9. Simulation analyses, based on a two-step interfacial ET model for the scanning tunneling microscopy redox process, were performed and provide quantitative information for rational understanding of the ET mechanism.blue copper protein ͉ scanning tunneling microscopy ͉ nanoscale bioelectronics ͉ bioelectrochemistry C harge transfer plays key roles in many chemical and biological processes as well as in molecular electronics (1-5). For example, long-range protein electron transfer (ET) is central in aerobic respiration and photosynthesis. The importance of longrange ET is illustrated by a recent special issue of PNAS on this topic (6-12). Several articles reflect broadly the current status of this subject. However, one of the major objectives in nanoscale science and technology is to fabricate molecular electronic devices with specified functions. Molecular electronics is rooted in the concept of molecular charge transfer (particularly, molecular conductivity) (13,14). Two essential steps involved in bottom-up manipulations are (i) organizing molecules into nanoscale structures and (ii) interfacing such nanostructures with macroscopically addressable components (e.g., metal and semiconductor electrodes). Molecular electronic device function thus rests fundamentally on charge transfer through organic and͞or biological molecules and across the interface between molecules and macroscopic electrodes (15, 16). Understanding of charge transfer mechanisms has mostly been based on average results of macroscopic measurements. The advent of scanning probe microscopies, along with other supersensitive techniques, has made it possible to characterize or directly observe charge transfer through organic molecules down to the nanoscale and single-molecule levels, as illustrated by measurements of singlemolecule conductivity (17-21) and probing of molecular switching and resonant tunneling (22,23). This, however, remains a daunting challenge for proteins, with difficulties arising from the assembly of suitable st...

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“…The disul®de bond, located in the`southern pole' of PC as opposed to the type I Cu site located in the`northern pole', is expected to provide an anchoring group for chemisorption onto gold substrates. Such a strategy of thiol gold immobilization has been previously exploited in azurin, an homologous Cu protein that also bears a native disul®de bond, although differently located to that engineered in PC (Friis et al, 1997(Friis et al, , 1998(Friis et al, , 1999Chi et al, 2000;Facci et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

The 1.6 Å resolution crystal structure of a mutant plastocyanin bearing a 21–25 engineered disulfide bridge

Milani

Andolfi²,

Cannistraro³

et al. 2001

Acta Crystallogr D Biol Cryst

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Plastocyanin is an electron-transfer protein which has been largely used for biophysical studies as well as for protein-engineering experiments. A surface disul®de bridge has been engineered in poplar plastocyanin to allow protein chemisorption on gold substrates. The mutated plastocyanin crystal structure has been studied at 1.6 A Ê resolution (R factor = 0.145, R free = 0.205) to characterize the effects of the engineered disul®de on the overall protein structure and on the Cu-coordination sphere in view of biophysical applications. The new orthorhombic crystal form isolated for the mutated plastocyanin displays two protein molecules per asymmetric unit.

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Molecular Monolayers and Interfacial Electron Transfer ofPseudomonas aeruginosaAzurin on Au(111)

Cited by 256 publications

References 49 publications

Direct measurement and modulation of single-molecule coordinative bonding forces in a transition metal complex

Direct measurement and modulation of single-molecule coordinative bonding forces in a transition metal complex

Long-range protein electron transfer observed at the single-molecule level: In situ mapping of redox-gated tunneling resonance

The 1.6 Å resolution crystal structure of a mutant plastocyanin bearing a 21–25 engineered disulfide bridge

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