Metalloproteins
Mostrando 13-24 de 40 artigos, teses e dissertações.
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13. Estudo bioquimico e ultraestrutural da matriz extracelular durante atrofia experimental de glandulas submandibulares de ratos
Obstructive atrophy of salivary glands is a common disease. It may occur by ductal obstruction caused by calculus, infection or neoplastic processes. In the present work we have used electron microscopy and biochemical methods to study the changes that occur in the expression laminin, type IV collagen and metaloproteinases during the experimental atrophy of
Publicado em: 1996
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14. Retrostructural analysis of metalloproteins: Application to the design of a minimal model for diiron proteins
De novo protein design provides an attractive approach for the construction of models to probe the features required for function of complex metalloproteins. The metal-binding sites of many metalloproteins lie between multiple elements of secondary structure, inviting a retrostructural approach to constructing minimal models of their active sites. The backbo
National Academy of Sciences.
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15. An approach to long-range electron transfer mechanisms in metalloproteins: In situ scanning tunneling microscopy with submolecular resolution
In situ scanning tunneling microscopy (STM) of redox molecules, in aqueous solution, shows interesting analogies and differences compared with interfacial electrochemical electron transfer (ET) and ET in homogeneous solution. This is because the redox level represents a deep indentation in the tunnel barrier, with possible temporary electronic populatio
The National Academy of Sciences.
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16. Papillomavirus polypeptides E6 and E7 are zinc-binding proteins.
Papillomavirus proteins E6 and E7 have Cys-X-X-Cys repeats which have been suggested to mediate zinc binding. We have developed a modification of an assay that detects zinc binding to proteins immobilized on filters. Using well-characterized metalloproteins, we show that, under reducing conditions, this assay distinguishes proteins that coordinate zinc throu
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17. PROMISE: a database of bioinorganic motifs.
The PROMISE (prosthetic centres andmetalions in protein activesites) database aims to present comprehensive sequence, structural, functional and bibliographic information on metalloproteins and other complex proteins, with an emphasis on active site structure and function. The database is available on the WorldWide Web at http://bioinf.leeds.ac.uk/promise/
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18. Direct vibrational structure of protein metal-binding sites from near-infrared Yb3+ vibronic side band spectroscopy.
Near-infrared Yb3+ vibronic side band (VSB) spectroscopy is used to obtain structural information of metal binding sites in metalloproteins. This technique provides a selective "IR-like" vibrational spectrum of those ligands chelated to the Yb3+ ion. VSB spectra of various model complexes of Yb3+ representing different ligand types were studied to provide re
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19. The bioinorganic chemistry of iron in oxygenases and supramolecular assemblies
The bioinorganic chemistry of iron is central to life processes. Organisms must recruit iron from their environment, control iron storage and trafficking within cells, assemble the complex, iron-containing redox cofactors of metalloproteins, and manage a myriad of biochemical transformations by those enzymes. The coordination chemistry and the variable oxida
The National Academy of Sciences.
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20. Inhibition of bacterial DNA replication by zinc mobilization during nitrosative stress
Phagocytic cells inhibit the growth of intracellular pathogens by producing nitric oxide (NO). NO causes cell filamentation, induction of the SOS response, and DNA replication arrest in the Gram-negative bacterium Salmonella enterica. NO also induces double-stranded chromosomal breaks in replication-arrested Salmonella lacking a functional RecBCD exonuc
National Academy of Sciences.
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21. De novo designed cyclic-peptide heme complexes
The structural characterization of de novo designed metalloproteins together with determination of chemical reactivity can provide a detailed understanding of the relationship between protein structure and functional properties. Toward this goal, we have prepared a series of cyclic peptides that bind to water-soluble metalloporphyrins (FeIII and CoIII). Neut
National Academy of Sciences.
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22. Modular synthesis of de novo-designed metalloproteins for light-induced electron transfer
The design and chemical synthesis of two de novo four-helix bundle proteins is described; each protein has two bound cofactors. Their construction from purified peptides is based on the modular assembly of different amphiphilic helices by chemoselective coupling to a cyclic peptide template. In the hydrophobic interior of the antiparallel four-helix bundle t
The National Academy of Sciences.
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23. Peripheral heme substituents control the hydrogen-atom abstraction chemistry in cytochromes P450
We elucidate the hydroxylation of camphor by cytochrome P450 with the use of density functional and mixed quantum mechanics/molecular mechanics methods. Our results reveal that the enzyme catalyzes the hydrogen-atom abstraction step with a remarkably low free-energy barrier. This result provides a satisfactory explanation for the experimental failure to
National Academy of Sciences.
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24. Proposed structure for the zinc-binding domains from transcription factor IIIA and related proteins.
Several proteins, including the gene regulatory protein transcription factor IIIA, have been shown to contain tandem repeats of sequences of approximately equal to 30 amino acids that are believed to form structural domains around bound zinc ions ("zinc fingers"). The consensus sequence for these repeats is (Phe, Tyr)-Xaa-Cys-(Xaa)2 or 4-Cys-(Xaa)3-Phe-(Xaa)