Search results for "Catalysis"
showing 10 items of 5944 documents
Photoinduced DNA damage efficiency and cytotoxicity of novel viologen linked pyrene conjugates.
2010
Novel viologen linked pyrene conjugates permeate cells efficiently and exhibit spacer length dependent DNA damage and cytotoxicity upon photoexcitation.
Oligonucleotide-capped mesoporous silica nanoparticles as DNA-responsive dye delivery systems for genomic DNA detection
2015
[EN] New hybrid oligonucleotide-capped mesoporous silica nanoparticles able to detect genomic DNA were designed.
Selective, Highly Sensitive, and Rapid Detection of Genomic DNA by Using Gated Materials:MycoplasmaDetection
2013
The coupling of gated-indicator delivery with highly specific biochemical recognition is an innovative strategy for the detection of DNA sequences, able to compete with classical methods which need PCR amplification, in important areas such as point-of-care diagnostics or detection of specific biological contaminations with pathogens. Such comparatively simple and cheap yet highly selective and sensitive assays hold promise for use in less-developed areas of the world.
Engineering of a bacterial tyrosinase for improved catalytic efficiency towards D-tyrosine using random and site directed mutagenesis approaches
2013
The tyrosinase gene from Ralstonia solanacearum (GenBank NP518458) was subjected to random mutagenesis resulting in tyrosinase variants (RVC10 and RV145) with up to 3.2-fold improvement in kcat, 5.2-fold lower Km and 16-fold improvement in catalytic efficiency for D-tyrosine. Based on RVC10 and RV145 mutated sequences, single mutation variants were generated with all variants showing increased kcat for D-tyrosine compared to the wild type (WT). All single mutation variants based on RV145 had a higher kcat and Km value compared to the RV145 and thus the combination of four mutations in RV145 was antagonistic for turnover, but synergistic for affinity of the enzyme for D-tyrosine. Single muta…
Arginine kinase in the demosponge Suberites domuncula:regulation of its expression and catalytic activity by silicic acid
2005
SUMMARY In Demospongiae (phylum Porifera) the formation of the siliceous skeleton,composed of spicules, is an energetically expensive reaction. The present study demonstrates that primmorphs from the demosponge Suberites domuncula express the gene for arginine kinase after exposure to exogenous silicic acid. The deduced sponge arginine kinase sequence displays the two characteristic domains of the ATP:guanido phosphotransferases; it can be grouped to the `usual' mono-domain 40 kDa guanidino kinases (arginine kinases). Phylogenetic studies indicate that the metazoan guanidino kinases evolved from this ancestral sponge enzyme; among them are also the `unusual'two-domain 80 kDa guanidino kinas…
Experimental indication in favor of the introns-late theory: the receptor tyrosine kinase gene from the sponge Geodia cydonium.
1997
Abstract We have analyzed the gene that encodes receptor tyrosine kinase (RTK) from the marine sponge Geodia cydonium, which belongs to the most ancient and simple metazoan groups, the Porifera. RTKs are enzymes found only in metazoa. The sponge gene contains two introns in the extracellular part of the protein. However, the rest of the protein (transmembrane and intracellular part), including the tyrosine kinase (TK)-domain, is encoded by a single exon. In contrast, all TK genes, so far known only from higher animals (vertebrates), contain several introns especially in the TK-domain. The TK-domain of G. cydonium shows similarity with numerous members of receptor as well as nonreceptor TKs.…
Phylogenetic Position of the Hexactinellida Within the Phylum Porifera Based on the Amino Acid Sequence of the Protein Kinase C from Rhabdocalyptus d…
1998
Recent analyses of genes encoding proteins typical for multicellularity, especially adhesion molecules and receptors, favor the conclusion that all metazoan phyla, including the phylum Porifera (sponges), are of monophyletic origin. However, none of these data includes cDNA encoding a protein from the sponge class Hexactinellida. We have now isolated and characterized the cDNA encoding a protein kinase C, belonging to the C subfamily (cPKC), from the hexactinellid sponge Rhabdocalyptus dawsoni. The two conserved regions, the regulatory part with the pseudosubstrate site, the two zinc fingers, and the C2 domain, as well as the catalytic domain were used for phylogenetic analyses. Sequence al…
Inverse Conformational Selection in Lipid–Protein Binding
2021
International audience; Interest in lipid interactions with proteins and other biomolecules is emerging not only in fundamental biochemistry but also in the field of nanobiotechnology where lipids are commonly used, for example, in carriers of mRNA vaccines. The outward-facing components of cellular membranes and lipid nanoparticles, the lipid headgroups, regulate membrane interactions with approaching substances, such as proteins, drugs, RNA, or viruses. Because lipid headgroup conformational ensembles have not been experimentally determined in physiologically relevant conditions, an essential question about their interactions with other biomolecules remains unanswered: Do headgroups excha…
Slow Magnetic Relaxation in a Co (II)–Y (III) Single‐Ion Magnet with Positive Axial Zero‐Field Splitting
2013
This work was supported by the MINECO (Spain) (Project CTQ2011-24478), the Junta de Andalucía (FQM-195 and Project of excellence P08-FQM-03705), and the University of Granada. E.R. and E.Cr. thank MINECO grant No. CTQ2011-23862-C02-01 and Generalitat de Catalunya grant No. 2009SGR-1459, for financial support. We would like to thank Prof. Liviu Chibotaru for providing us the SINGLE_ANISO program and Dr. Andrew Ozarowski for the EPR simulation software. E.K.B. thanks the EPSRC and Leverhulme Trust for financial support. The NHMFL is funded by the NSF, DoE, and the state of Florida. J.C. acknowledges financial support by the Spanish Ministerio de Ciencia e Innovación through projects CTQ2010-1…