Azurin for Biomolecular Electronics: a Reliability Study

Bramanti, A.; Pompa, Pier Paolo; Maruccio, Giuseppe; Calabi, Franco; Arima, Valentina; Cingolani, R.; Corni, Stefano; Felice, Rosa Di; Rienzo, Francesca De; Rinaldi, R.

doi:10.1143/jjap.44.6864

Cited by 8 publications

(13 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The combination of fast redox cycling with synthetic flexibility makes azurins promising active components of molecular devices (biomemories or rectifiers). 18-24 Photoactive azurin mutants can be prepared by appending Re(CO) 3 (diimine) photosensitizers to single surface exposed histidine residues and reducing Cu II to Cu I . Upon near-UV excitation, the metallolabeled proteins can undergo long-range ET from Cu I to the electronically excited Re I complex (*Re), with the kinetics dependent on the length and nature of the ET pathways.…”

Section: Introductionmentioning

confidence: 99%

Tryptophan-Accelerated Electron Flow Across a Protein–Protein Interface

et al. 2013

View full text Add to dashboard Cite

We report a new metallolabeled blue copper protein, Re126W122CuI Pseudomonas aeruginosa azurin, which has three redo sites at well-defined distances in the protein fold: ReI(CO)3(4,7-dimethyl-1,10-phenanthroline) covalently bound at H126, a Cu center, and an indole side chain W122 situated between the Re and Cu sites (Re-W122(indole) = 13.1 Å; dmp-W122(indole) = 10.0 Å, Re-Cu = 25.6 Å). Near-UV excitation of the Re chromophore leads to prompt CuI oxidation (<50 ns), followed by slow back ET to regenerate CuI and ground-state ReI with biexponential kinetics, 220 ns and 6 μs. From spectroscopic measurements of kinetics and relative ET yields at different concentrations, it is likely that the photoinduced ET reactions occur in protein dimers, (Re126W122CuI)2, and that the forward ET is accelerated by intermolecular electron hopping through the interfacial tryptophan: *Re//←W122←CuI, where // denotes a protein-protein interface. Solution mass spectrometry confirms a broad oligomer distribution with prevalent monomers and dimers, and the crystal structure of the CuII form shows two Re126W122CuII molecules oriented such that redox cofactors Re(dmp) and W122-indole on different protein molecules are located at the interface at much shorter intermolecular distances (Re-W122(indole) = 6.9 Å, dmp-W122(indole) = 3.5 Å, and Re-Cu = 14.0 Å) than within single protein folds. Whereas forward ET is accelerated by hopping through W122, BET is retarded by a space jump at the interface that lacks specific interactions or water molecules. These findings on interfacial electron hopping in (Re126W122CuI)2 shed new light on optimal redox-unit placements required for functional long-range charge separation in protein complexes.

show abstract

Section: Introductionmentioning

confidence: 99%

Tryptophan-Accelerated Electron Flow Across a Protein–Protein Interface

et al. 2013

View full text Add to dashboard Cite

show abstract

“…The Cu II /Cu I redox couple is reversible and the Cu oxidation state can be switched photochemically or electrochemically, making azurins promising candidates for applications in molecular devices, such as biomemories or rectifiers. 17,19–21 …”

Section: Introductionmentioning

confidence: 99%

Mass Spectrometric Characterization of Oligomers in Pseudomonas aeruginosa Azurin Solutions

et al. 2011

View full text Add to dashboard Cite

We have employed laser induced liquid bead ion desorption mass spectroscopy (LILBID MS) to study the solution behavior of Pseudomonas aeruginosa azurin as well as two mutants and corresponding Re-labeled derivatives containing a Re(CO)3(4,7-dimethyl-1,10-phenanthroline) chromophore appended to a surface histidine. LILBID spectra show broad oligomer distributions whose particular patterns depend on the solution composition (pure H2O, 20–30 mM NaCl, 20 and 50 mM NaPi or NH4Pi at pH = 7). The distribution maximum shifts to smaller oligomers upon decreasing the azurin concentration and increasing the buffer concentration. Oligomerization is less extensive for native azurin than its mutants. The oligomerization propensities of unlabeled and Re-labeled proteins are generally comparable, only Re126 shows some preference for the dimer that persists even in highly diluted solutions. Peak shifts to higher masses and broadening in 20–50 mM NaPi confirm strong azurin association with buffer ions and solvation. We have found that LILBID MS reveals the solution behavior of weakly bound nonspecific oligomers, clearly distinguishing individual components of the oligomer distribution. Independently, average data on oligomerization and the dependence on solution composition were obtained by time-resolved anisotropy of the Re-label photoluminescence that confirmed relatively long rotation correlation times, 6–30 ns, depending on Re-azurin and solution composition. Labeling proteins with Re-chromophores that have long-lived phosphorescence extends the timescale of anisotropy measurements to hundreds of ns, thereby opening the way for investigations of large oligomers with long rotation times.

show abstract

“…1a, is the active site of the histidine amino acid, which is an important ligand in biochemistry. The binding characteristic of imidazole is due to the lone pair of the N atom from the imino group which actively participate in many complexes with metals as, for example, at the Cu site in the blue copper protein Azurin [1]. A relevant aspect is the modification of the local electronic orbitals when submitted to different ambient conditions as in a biological environment or condensed matter phase.…”

Section: Introductionmentioning

confidence: 99%

Ab initio study of the EFG at the N sites in imidazole

Gonçalves

Felice²,

Полещук

et al. 2008

Hyperfine Interact

View full text Add to dashboard Cite

We study the nuclear quadrupole interaction at the nitrogen sites in the molecular and crystalline phases of the imidazole compound. We use PAW which is a state-of-the-art method to calculate the electronic structure and electric field gradient at the nucleus in the framework of the density functional theory. The quadrupole frequencies at both imino and amino N sites are in excellent agreement with measurements. This is the first time that the electric field gradient at crystalline imidazole is correctly treated by an ab initio theoretical approach.

show abstract

Azurin for Biomolecular Electronics: a Reliability Study

Cited by 8 publications

References 15 publications

Tryptophan-Accelerated Electron Flow Across a Protein–Protein Interface

Tryptophan-Accelerated Electron Flow Across a Protein–Protein Interface

Mass Spectrometric Characterization of Oligomers in Pseudomonas aeruginosa Azurin Solutions

Ab initio study of the EFG at the N sites in imidazole

Contact Info

Product

Resources

About