A 16-amino acid residue peptide derived from a consensus motif of natural ferredoxins incorporates tetranuclear iron sulfur cluster under physiological conditions. Successful assembly the [4Fe–4S] 2+/1+ within monomeric was demonstrated using size exclusion chromatography, UV-visible, visible CD, and cryogenic EPR spectroscopies. The robustness formation tested peptides with either ligating cysteine exchanged for alanine or intervening amino acids replaced by glycine. small allows modular...

The effects of various mechanisms metalloporphyrin reduction potential modulation were investigated experimentally using a robust, well-characterized heme protein maquette, synthetic scaffold H10A24 [{CH3CONH-CGGGELWKL·HEELLKK·FEELLKL·AEERLKK·L-CONH2}2]2. Removal the iron porphyrin macrocycle from high dielectric aqueous environment and sequestration within hydrophobic core maquette raises equilibrium midpoint by 36−138 mV depending on hydrophobicity structure. By incorporating natural...

Biotin synthase is an iron−sulfur protein that utilizes AdoMet to catalyze the presumed radical-mediated insertion of a sulfur atom between saturated C6 and C9 carbons dethiobiotin. (BioB) aerobically purified as dimer contains [2Fe-2S]2+ clusters inactive in absence additional iron reductants, anaerobic reduction BioB with sodium dithionite results conversion enzyme containing [4Fe-4S]2+ and/or [4Fe-4S]+ clusters. To establish predominant cluster forms present biotin assays, by inference...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCopper(II) 12-Metallacrown-4: Synthesis, Structure, Ligand Variability, and Solution Dynamics in the 12-MC-4 Structural MotifBrian R. Gibney, Dimitris P. Kessissoglou, Jeff W. Kampf, Vincent L. PecoraroCite this: Inorg. Chem. 1994, 33, 22, 4840–4849Publication Date (Print):October 1, 1994Publication History Published online1 May 2002Published inissue 1 October...

Proteins containing heme, iron(protoporphyrin IX) and its variants, continue to be one of the most-studied classes biomolecules due their diverse range biological functions. The literature is abundant with reports structural functional characterization individual heme proteins which demonstrate that protein reduction potential values, E(m), span from -550 mV +450 versus SHE. In order unite these data for purposes global analysis, a new web-based resource structure-function relationships...

Bacterial microcompartments (BMCs) are self-assembling organelles composed of a selectively permeable protein shell and encapsulated enzymes. They considered promising templates for the engineering designed bionanoreactors biotechnology. In particular, encapsulation oxidoreductive reactions requiring electron transfer between lumen BMC cytosol relies on ability to conduct electrons across shell. We determined crystal structure component synthetic shell, which informed rational design...

The preparation of a variety salt complexes [12-MCMn(III)N(shi)-4] (1) provides the structural basis for first quantitative investigation cation and anion selectivity metallacrowns. preparation, X-ray crystal structures, solution integrities crystalline salts (LiCl2)[12-MCMn(III)N(shi)-4]- ([(LiCl2)·1]-), (Li(trifluoroacetate))[12-MCMn(III)N(shi)-4] ([(LiTFA)·1]), (Li)[12-MCMn(III)N(shi)-4]+ ([(Li)·1]+), (NaBr)2[12-MCMn(III)N(shi)-4] ([(NaBr)2·1]), (KBr)2[12-MCMn(III)N(shi)-4] ([(KBr)2·1])...

Zinc finger transcription factors represent the largest single class of metalloproteins in human genome. Binding Zn(II) to their canonical Cys4, Cys3His1, or Cys2His2 sites results metal-induced protein folding events required achieve proper structure for biological activity. The thermodynamic contribution each these coordination spheres toward is poorly understood because coupled nature metal-ligand and protein-protein interactions. Using an unstructured peptide scaffold, GGG, we have...

Water is essential to human health and economic development due its utilization in sanitation, agriculture, energy. Supplying water an expanding world population requires simultaneous consideration of multiple societal sectors competing for limited resources. conservation, supply augmentation, distribution, treatment contaminants must work concert ensure sustainability. linked other sectors, the quantity quality resources are changing. The efficient use largest user worldwide, via drip...

Biotin synthase catalyzes the insertion of a sulfur atom into saturated C6 and C9 carbons dethiobiotin. This reaction has long been presumed to occur through radical chemistry, recent experimental results suggest that biotin belongs family enzymes contain an iron−sulfur cluster reductively cleave S-adenosylmethionine, forming enzyme or substrate radical, 5'-deoxyadenosine, methionine. (BioB) is aerobically purified as dimer 38 kDa monomers contains two [2Fe-2S]2+ clusters per dimer. Maximal...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe fused metallacrown anion Na2{[Na0.5[Ga(salicylhydroximate)]4]2(.mu.2-OH)4}- is an inorganic analog of a cryptateMyoung Soo Lah, Brian R. Gibney, David L. Tierney, James E. Penner-Hahn, and Vincent PecoraroCite this: J. Am. Chem. Soc. 1993, 115, 13, 5857–5858Publication Date (Print):June 1, 1993Publication History Published online1 May 2002Published inissue 1 June...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTGeneralizing the metallacrown analogy: ligand variation and solution stability of VVO 9-metallacrown-3 structure typeBrian R. Gibney, Ann J. Stemmler, Steffen Pilotek, Jeff W. Kampf, Vincent L. PecoraroCite this: Inorg. Chem. 1993, 32, 26, 6008–6015Publication Date (Print):December 1, 1993Publication History Published online1 May 2002Published inissue 1 December...

Heme A, a prosthetic group of cytochrome c oxidase [EC 1.9.3.1], has been introduced into two de novo designed four helix bundle proteins, [H10A24]2 and [H10H24]2, known to bind 2−4 equiv heme B, respectively [Robertson, D. E., Farid, R. S., Moser, C. C., Mulholland, S. Pidikiti, R., Lear, J. D., Wand, A., J., DeGrado, W. F., Dutton, P. L. (1994) Nature 368, 425−432]. [H10A24]2, {[Ac-CGGGELWKL·HEELLKK·FEELLKL·AEERLKK·L-CONH2]2}2, binds A molecules per four-helix unit via bis-histidine...

A survey of ferredoxin maquettes derived from natural sequences was utilized to obtain a primary sequence competent for [4Fe-4S]2+/+ incorporation the study minimal ligand requirements cluster assembly. The resultant 16 amino acid maquette (FdM), NH2-KLCEGG•CIACGAC•GGW-CONH2, incorporates single as evidenced by titration assayed electron paramagnetic resonance (EPR) spectroscopy. Assembly [4Fe-4S] within FdM kinetically facile (minutes time scale) and stable in solution under strictly...

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTDesign of a Unique Protein Scaffold for MaquettesBrian R. Gibney, Francesc Rabanal, Jack J. Skalicky, A. Joshua Wand, and P. Leslie DuttonView Author Information The Johnson Research Foundation, Department Biochemistry Biophysics, University Pennsylvania Philadelphia, 19104 Departments Chemistry, Biological Sciences, Biophysical Sciences Center Structural Biology State New York Buffalo, 14260−3000 Cite this: Am. Chem. Soc. 1997, 119, 9,...

An iterative redesign protocol for the transformation of a non-native peptide into series nativelike proteins derived from elementary considerations biological evolution coupled with 1H NMR as an artificial selection criterion is presented. Each three heptad d position leucines in helix−helix interfaces prototype heme protein maquette, [H10H24]2 or (α-SS-α)2, were replaced unit modification per helix by more conformationally restricted β-branched and aromatic amino acids. The secondary...

The solution structure of a de novo designed disulfide-bridged two-α-helix peptide that self-assembles to form 2-fold symmetric four-α-helix bundle protein (α'-SS-α')2 has been solved by NMR spectroscopy. 33-residue peptide, (α'-SH), is the basic building block recombinantly expressed. three-dimensional asymmetric unit determined using interproton distance restraints derived from nuclear Overhauser effect (NOE), covalent torsion angle three bond scalar coupling constants, and longer range...

The prototype ferredoxin maquette, FdM, is a 16-amino acid peptide which efficiently incorporates single [4Fe-4S]2+/+ cluster with spectroscopic and electrochemical properties that are typical of natural bacterial ferredoxins. Using this synthetic protein scaffold, we have investigated the role nonliganding amino acids in assembly iron−sulfur cluster. In stepwise fashion, truncated FdM to seven-amino peptide, FdM-7, spectroscopically identical but lower yield, 29% relative FdM. FdM-7...

We have designed two alternative four helix bundle protein scaffold topologies for maquette construction to examine the effect of orientation on heme binding and redox properties our prototype maquette, (α-SS-α)2, previously described as H10H24 [Robertson, D. E., Farid, R. S., Moser, C. C., Mulholland, S. Pidikiti, R., Lear, J. D., Wand, A. J., DeGrado, W. F., Dutton, P. L. (1994) Nature 368, 425]. Conversion disulfide-bridged di-α-helical monomer (α-SS-α)2 into a single polypeptide chain...

The presence of a two-subunit cytochrome (cyt) b−c1 subcomplex in chromatophore membranes Rhodobacter capsulatus mutants lacking the Rieske iron−sulfur (Fe-S) protein has been described previously [Davidson, E., Ohnishi, T., Tokito, M., and Daldal, F. (1992) Biochemistry 31, 3351−3358]. Here, this was purified to homogeneity large quantities, its properties were characterized. As expected, it contained stoichiometric amounts cyt b c1 subunits forming stable entity devoid Fe-S subunit....

A maleimide nitroxide spin-label (MAL-6) linked to a cysteine in the hydrophobic core and coproporphyrin I (CP) appended on N-terminus of synthetic helix−loop−helix peptide ([α2]) have been used examine designed self-association four-helix bundle ([α2]2), focusing topology stability rotational dynamics spin-label. Gel-permeation chromatography demonstrated that [α2] modified with ([MAL-6-α2]), ([CP-α2]) plus ([CP-MAL-6-α2]) self-associate into four helix bundles solution as designed....

Metal−ligand interactions are critical components of metalloprotein assembly, folding, stability, electrochemistry, and catalytic function. Research over the past 3 decades on interaction metals with peptide protein ligands has progressed from characterization amino acid−metal polypeptide−metal complexes to design folded scaffolds containing multiple metal cofactors. De novo emerged as a valuable tool both for modular synthesis these complex metalloproteins revealing fundamental tenets...