An experimental determination of the thermodynamic stabilities a series amyloid fibrils reveals that this structural form is likely to be most stable one protein molecules can adopt even under physiological conditions. This result challenges conventional assumption functional forms proteins correspond global minima in their free energy surfaces and suggests living systems are conformationally as well chemically metastable.

Protein amyloid fibrils can be functionalized by coating the core protofilament with high concentrations of proteins and enzymes. This done elegantly appending a functional domain to an amyloidogenic protein monomer, then assembling monomers into fibril. To display array biologically porphyrins on surface fibrils, we have fused sequence small, soluble cytochrome b562 SH3 dimer that form classical rapidly under well-defined conditions. The resulting fusion also forms and, in addition, binds...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTpH-Linked conformational regulation of a metalloprotein oxidation-reduction equilibrium: electrochemical analysis the alkaline form cytochrome cPaul D. Barker and A. Grant MaukCite this: J. Am. Chem. Soc. 1992, 114, 10, 3619–3624Publication Date (Print):May 1, 1992Publication History Published online1 May 2002Published inissue 1 1992https://pubs.acs.org/doi/10.1021/ja00036a006https://doi.org/10.1021/ja00036a006research-articleACS...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEffects of charged amino acid mutations on the bimolecular kinetics reduction yeast iso-1-ferricytochrome c by bovine ferrocytochrome b5Scott H. Northrup, Kathryn A. Thomasson, Cynthia M. Miller, Paul D. Barker, Lindsay Eltis, J. Guy Guillemette, Grant Mauk, and Stephen C. InglisCite this: Biochemistry 1993, 32, 26, 6613–6623Publication Date (Print):July 1, 1993Publication History Published online1 May 2002Published inissue 1 July...

Residue Asn57 of bovine liver cytochrome b5 has been replaced with a cysteine residue, and the resulting variant isolated from recombinant Escherichia coli as mixture four major species: A, BI, BII, C. A combination electronic spectroscopy, 1H NMR resonance Raman electrospray mass spectrometry, direct electrochemistry used to characterize these derivatives. The red form (E(m) = -19 mV) is found possess heme group bound covalently through thioether linkage involving Cys57 alpha carbon 4-vinyl...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectrochemical, kinetic, and circular dichroic consequences of mutations at position 82 yeast iso-1-cytochrome cSteven P. Rafferty, Linda L. Pearce, Paul D. Barker, J. Guy Guillemette, Cyril M. Kay, Michael Smith, A. Grant MaukCite this: Biochemistry 1990, 29, 40, 9365–9369Publication Date (Print):October 1, 1990Publication History Published online1 May 2002Published inissue 1 October...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTConversion of Cytochrome b562 to c-Type CytochromesPaul D. Barker, Edmund P. Nerou, Stefan M. V. Freund, and Ian FearnleyCite this: Biochemistry 1995, 34, 46, 15191–15203Publication Date (Print):November 1, 1995Publication History Published online1 May 2002Published inissue 1 November 1995https://pubs.acs.org/doi/10.1021/bi00046a027https://doi.org/10.1021/bi00046a027research-articleACS PublicationsRequest reuse permissionsArticle...

Starch is a prominent component of the human diet and hydrolyzed by α-amylase post-ingestion. Probing mechanism this process has proven challenging, due to intrinsic heterogeneity individual starch granules. By means solution-state NMR, we demonstrate that flexible polysaccharide chains protruding from solvent-exposed surfaces waxy rice granules are highly mobile during hydrothermal treatment, when swell, number residues on exposed increases factor 15. Moreover, show these primary substrates...

The solution structure of the oxidized, paramagnetic form cytochrome b562 from Escherichia coli (106 amino acids) is here reported as obtained 1653 meaningful NOEs (from a total 2051 unique NOEs), 33 3JHNHα values, and 339 pseudocontact shifts. displays typical four-helix bundle motif, disordered loop between helices α2 α3, found in solid state. has conformation intermediate two independent solid-state molecules, although different orientations are observed for few residues. magnetic...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTReduction of horse heart ferricytochrome c by bovine liver ferrocytochrome b5. Experimental and theoretical analysisLindsay D. Eltis, Robert G. Herbert, Paul Barker, A. Grant Mauk, Scott H. NorthrupCite this: Biochemistry 1991, 30, 15, 3663–3674Publication Date (Print):April 16, 1991Publication History Published online1 May 2002Published inissue 16 April...

The electron transfer reactions of four small redox proteins, cytochrome c , ferredoxin, plastocyanin and azurin, have been investigated at novel peptide‐modified gold electrodes. These proved to be effective selective in facilitating transfer. Good, quasi‐reversible was achieved selectively different peptide‐protein configurations by changing the pH or ionic strength solution. use peptides as promoters for protein electrochemistry opens up possibility designing very specific electrode...

Abstract Previous theoretical studies of C 3 B have suggested that boron‐doped graphite is a promising H 2 ‐ and Li‐storage material, with large maximum capacities. These characteristics could lead to exciting applications as lightweight ‐storage material for automotive engines an anode in new generation batteries. However, these be realized synthetic route bulk must developed. Here we show the thermolysis single‐source precursor (1,3‐(BBr ) 6 4 produce graphitic B, thus allowing this...

This perspective seeks to discuss why biology often modifies the fundamental iron-protoporphyrin IX moiety that is very versatile cofactor of many heme proteins. A common modification attachment this via covalent bonds two (or rarely one) sulfur atoms cysteine residue side chains. results in c-type cytochromes, which have diverse structures and functions. The are made different ways depending on cell type. There little understanding reasons for complexity assembly routes but proposals...

Telling fibrils: Diffusion data obtained by solution NMR spectroscopy from flexible regions of amyloid fibrils for both rotational and translation diffusion combined is similar magnitude to that measured using AFM TEM (see picture). Fibrils in are calculated be somewhat longer on average than those deposited surfaces microscopy experiments, which can partially attributed the sensitivity fracture. Supporting information this article available WWW under...

The construction of useful functional biomolecular components not currently part the natural repertoire is central to synthetic biology. A new light-capturing ultra-high-efficiency energy transfer protein scaffold has been constructed by coupling chromophore centers two normally unrelated proteins: autofluorescent enhanced green fluorescent (EGFP) and heme-binding electron cytochrome b(562) (cyt b(562)). Using a combinatorial domain insertion strategy, variant was isolated in which resonance...

Abstract We have recently demonstrated a novel anaerobic NADH‐dependent haem breakdown reaction, which is carried out by range of haemoproteins. The Yersinia enterocolitica protein, HemS, the focus further research presented in current paper. Using conventional experimental methods, bioinformatics, and energy landscape theory (ELT), we provide new insight into mechanism process. Of particular interest behavior double phenylalanine gate, opens closes according to relative situations NADH...

Enzyme engineering and discovery are crucial for a sustainable future bioeconomy. Harvesting new biocatalysts from large libraries through directed evolution or functional metagenomics requires accessible, rapid assays. Ultrahigh-throughput screening formats often require optical readouts, leading to the use of model substrates that may misreport target activity necessitate bespoke synthesis. This is particular challenge when glycosyl hydrolases, which leverage molecular recognition beyond...

A new approach was developed to overproduce 15 N‐enriched yeast iso‐1‐cytochrome c in the periplasm of Escherichia coli order perform a study motions ms–µs time scale on oxidized and reduced forms through rotating frame N relaxation rates proton/deuterium exchange studies. It is confirmed that protein rather rigid whereas species more flexible. The regions display increased internal mobility upon oxidation are easily identified by number residues experiencing conformational equilibria their...

Cytochrome b562 is a periplasmic Escherichia coli protein; previous work has shown that heme can be attached covalently in vivo as consequence of introduction one or two cysteines into the heme-binding pocket. A heterogeneous mixture products was obtained, and it not established whether covalent bond formation catalyzed spontaneous. Here, we show coexpression from plasmids variant cytochrome containing CXXCH motif with E. c maturation (Ccm) proteins results an essentially homogeneous product...

We have generated mutants of cytochrome b562 in which the histidine ligand to heme iron (His102) has been replaced by a methionine. The resulting proteins can bis-methionine coordination iron, but stability this arrangement is dependent on oxidation state and solution pH. used optical, MCD, EPR spectroscopies study nature environment under variety conditions. Optical spectra reduced single variant, H102M, are consistent with ligation. In its oxidized state, protein high-spin all conditions...

The covalent attachment of the heme cofactor in c-type cytochromes is a surprisingly complex process, which bacteria involves number different proteins. Among latter, ccmE gene product known to perform key role delivery pathway Gram-negative bacteria. solution structure soluble domain apo-CcmE from Shewanella putrefaciens was determined through NMR spectroscopy on 13C,15N-labeled sample. characterized by compact core with large regions β structure, while N-terminal and C-terminal are...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDirect electrochemistry of protein-protein complexes involving cytochrome c, b5, and plastocyaninStefan Bagby, Paul D. Barker, Liang Hong Guo, H. Allen O. HillCite this: Biochemistry 1990, 29, 13, 3213–3219Publication Date (Print):April 3, 1990Publication History Published online1 May 2002Published inissue 3 April 1990https://pubs.acs.org/doi/10.1021/bi00465a010https://doi.org/10.1021/bi00465a010research-articleACS PublicationsRequest reuse...