Search results for "complexe"

The concentration of Cytochrome f and P700 in chlorophyll-deficient mutants of Chlorella fusca

1977

The ratio of Chlorophyll: Cytochrome f and of Chlorophyll: P700 (reaction center pigment in photosystem I) is essentially lower in chlorophyll-deficient mutants than in the normal green strain. On a dry weight basis, the mutants have the same or a higher content of redox enzymes than the normal form. The size of the photosynthetic unit of the mutants is 4 to 7 times smaller than that of the normal strains, due mainly to a deficiency of the light-harvesting chlorophyll-protein complex.

The sequence alteration associated with a mutational hotspot in p53 protects cells from lysis by cytotoxic T lymphocytes specific for a flanking pept…

1998

A high proportion of tumors arise due to mutation of the p53 tumor suppressor protein. A p53 hotspot mutation at amino acid position 273 from R to H, flanking a peptide epitope that spans residues 264–272, renders cells resistant to killing by human histocompatibility leukocyte antigen (HLA)-A*0201–restricted cytotoxic T lymphocytes (CTLs) specific for this epitope. Acquisition of the R to H mutation at residue 273 of the human p53 protein promotes tumor growth in vivo by selective escape from recognition by p53.264–272 peptide-specific CTLs. Synthetic 27-mer p53 polypeptides covering the antigenic nonamer region 264–272 of p53 were used as proteasome substrates to investigate whether the R…

Cascade complex formation by phosphate in the cobalt(II)/[30]aneN10 anaerobic system

1993

Abstract The interaction of phosphate with the mono- and binuclear cobalt(II) complexes of [30]aneN 10 (1,4,7,10,13,16,19,22,25,28-decaazacyclotriacontane) has been studied by potentiometry in 0.15 mol dm −3 NaClO 4 solution at 298.15 K under anaerobic conditions. The stable species [CoH 2 ([30]aneN 10 )PO 4 ] + , [CoH 4 ([30]aneN 10 )PO 4 ] 3+ , [Co 2 H([30]aneN 10 )PO 4 ] 2+ , [Co 2 H 2 ([30]aneN 10 )PO 4 ] 3+ and [Co 2 H 3 ([30]aneN 10 )PO 4 ] 4+ , where the phosphate anion is directly bound to the metal ions or acts as a second sphere ligand, are formed and their stability constants have been determined. The results obtained allowed for the selection of suitable conditions for the study…

THE INTERACTION OF NATIVE DNA WITH Ni(II), Cu(II) and Zn(II) COMPLEXES OF 5-TRIETHYL AMMONIUM METHYL SALICYLIDENE ORTHO-PHENYLENDIIMINE

2009

Purification of Leuconostoc mesenteroides citrate lyase and cloning and characterization of the citCDEFG gene cluster

1998

ABSTRACT A citrate lyase (EC 4.1.3.6 ) was purified 25-fold from Leuconostoc mesenteroides and was shown to contain three subunits. The first 42 amino acids of the β subunit were identified, as well as an internal peptide sequence spanning some 20 amino acids into the α subunit. Using degenerated primers from these sequences, we amplified a 1.2-kb DNA fragment by PCR from Leuconostoc mesenteroides subsp. cremoris . This fragment was used as a probe for screening a Leuconostoc genomic bank to identify the structural genes. The 2.7-kb gene cluster encoding citrate lyase of L. mesenteroides is organized in three open reading frames, citD , citE , and citF , encoding, respectively, the three ci…

Arbutin synthase, a novel member of the NRD1β glycosyltransferase family, is a unique multifunctional enzyme converting various natural products and …

2002

Plant glucosyltransferases (GTs) play a crucial role in natural product biosynthesis and metabolization of xenobiotics. We expressed the arbutin synthase (AS) cDNA from Rauvolfia serpentina cell suspension cultures in Escherichia coli with a 6 x His tag and purified the active enzyme to homogeneity. The recombinant enzyme had a temperature optimum of 50 degrees C and showed two different pH optima (4.5 and 6.8 or 7.5, depending on the buffer). Out of 74 natural and synthetic phenols and two cinnamyl alcohols tested as substrates for the AS, 45 were accepted, covering a broad range of structural features. Converting rates comparable to hydroquinone were not achieved. In contrast to this broa…

DNA Binding and Biological Activity of Transition Metal Complexes

2011

DNA interaction and biological activity of first row transition metal complexes

2011

Assembly of Polycomb complexes and silencing mechanisms

2003

Polycomb complexes assemble at their target sites and silence neighboring genes when these are not actively transcribed. The action of these complexes and of Trithorax complexes bound to the Polycomb Response Element establish alternative silent or derepressed states that are remembered through cell division and maintained for the rest of development. Recent results that may help explain the properties of these states are reviewed.

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…