1,721,114 research outputs found
Resistance in Candida albicans: exploring the cell wall barrier by proteomics
Full text linkThe incidence of candidiasis has dramatically increased and bloodstream infections due to different species of
Candida are becoming a prime cause of morbidity and mortality in different types of immunocompromised patients.
Azole and echinocandin drug resistance accounts for the dramatic increase in incidence of nosocomial bloodstream
candidiasis found in recent years. Cell wall constitutes the barrier between the yeast and the host and resistant
strains change the proteome of this compartment. In the last decade different proteomic platforms have been
applied to study cell wall and markers of resistance to drugs have been pointed out. Modulation of these proteins
seem to suggest that although resistance is based on a specific mutation able to counteract the toxicity of the
antifungal drug, a set of other molecular modifications takes place contemporary or subsequently the establishment
of the resistance and seems to support the viability of the resistant yeast. Profiled proteins by proteomics may be
valuable in design therapy using classical antifungal along with complementary drugs able to abolish pathways that
strengthen the resistance and attenuate virulence of the mutated cell
A chromophore in glutamate decarboxylase has been wrongly identified as PQQ
No full textPyrroloquinoline quinone (PQQ) has been claimed to be a component of glutamate decarboxylase from Escherichia coli on the basis of a frequently used procedure in which the protein is extracted with hexanol. We demonstrate that if pyridoxal phosphate (PLP) is not added during the preparation, the apoenzyme prepared from glutamate decarboxylase contains no chromophore absorbing above 280 nm. Full enzyme activity and the original holoenzyme spectrum are restored by the addition of PLP alone. A 340 nm-absorbing band, similar to that which prompted analysis for PQQ, is produced by exposure of the enzyme to solutions of PLP
Nuclear matrix localization of annexin V in chicken liver
No full textFractionation of internal matrix proteins from chicken liver nuclei led to the isolation of a 32 kDa protein which was identified by partial aminoacid sequence and immunological analysis as annexin V, an unreported nuclear matrix component. Our results showed that this protein is preferentially associated with the internal nuclear matrix fraction, since this is the only nuclear fraction where the protein can be immunodetected. Immunostaining on cultured cells also revealed a nuclear distribution with the exclusion of the nucleolar compartment and an association with cytosolic filamentous structures most likely corresponding to the cytoskeleton. Moreover, immunostaining on extracted cells to reveal the nuclear matrix showed a network-like distribution. Since annexin V has been reported as an inhibitor of protein kinase C, its nuclear localization in association with the internal matrix, which plays an important role in several nuclear processes, indicates its involvement in the regulation of signal transduction. (C) 1996 Academic Press, Inc
A chimeric mini-trypsin inhibitor derived from the oil rape proteinase inhibitor type III.
No full textTHERMODYNAMIC ANALYSIS OF THE BINDING OF THE POLYGLUTAMATE CHAIN OF 5-FORMYLTETRAHYDROPTEROYLPOLYGLUTAMATES TO SERINE HYDROXYMETHYLTRANSFERASE
No full textContributions of the substrate-binding arginine residues to maleate-induced closure of the active site of Escherichia coli aspartate aminotransferase.
No full textDifferent susceptibility of the two dimers of ribonuclease A to subtilisin. Implications for their structure
No full textRNase A and its minor and major dimers were digested with subtilisin under controlled conditions. The major dimer was found to be slightly more resistant, the minor dimer markedly less resistant to subtilisin than monomeric RNase A. Two S-proteins formed for each RNase A species, one starting with Ser-21 the other with Ser-22. Their relative proportions indicate that the structure of the minor dimer, whose identity with that of a RNase A dimer shown to be 3D domain-swapped is strongly suggested by recent work [S. Sorrentino et al. (2000) FEES Lett. 466, 35-39], makes its peptide bond between Ser-21 and Ser-22 more accessible to subtilisin than it is in RNase A and its major dimer. Moreover, (i) both subunits constituting the minor dimer are more susceptible to subtilisin than monomeric RNase A, and (ii) the susceptible bonds in one of its two exchanging N-terminal arms are more accessible to the protease than in the other. The properties of the major dimer suggest that its structure could be different. (C) 2001 Elsevier Science B.V. All rights reserved
The CM2 and CM3 types of alpha-amylase inhibitor are associated whit triticum aestivum seed chromatin.
No full textGlycine consumption and mitochondrial serine hydroxymethyltransferase in cancer cells: the heme connection
No full textIt was recently discovered that glycine consumption is strongly related to the rate of proliferation across cancer cells. This is very intriguing and raises the question of what is the actual role of this amino acid in cancer metabolism. Cancer cells are greedy for glycine. In particular, the mitochondrial production of glycine seems to be utterly important. Overexpression of mitochondrial serine hydroxymethyltransferase, the enzyme converting l-serine to glycine, assures an adequate supply of glycine to rapidly proliferating cancer cells. In fact, silencing of mitochondrial serine hydroxymethyltransferase was shown to halt cancer cell proliferation. Direct incorporation of glycine carbon atoms into the purine ring has been proposed to be one main reason for the importance of glycine in cancer cell metabolism.
We believe that, as far as the importance of glycine in cancer is concerned, a central role of this amino acid, namely its participation to heme biosynthesis, has been neglected. In mitochondria, glycine condenses with succinyl-CoA to form 5-aminolevulinate, the universal precursor of the different forms of heme contained in cytochromes and oxidative phosphorylation complexes.
Our hypothesis is that mitochondrial serine hydroxymethyltransferase is fundamental to sustain cancer metabolism since production of glycine fuels heme biosynthesis and therefore oxidative phosphorylation. Respiration of cancer cells may then ultimately rely on endogenous glycine synthesis by mitochondrial serine hydroxymethyltransferase. The link between mitochondrial serine hydroxymethyltransferase activity and heme biosynthesis represents an important and still unexplored aspect of the whole picture of cancer cell metabolism.
Our hypothesis might be tested using a combination of metabolic tracing and gene silencing on different cancer cell lines. The experiments should be devised so as to assess the importance of mitochondrial serine hydroxymethyltransferase and the glycine deriving from its reaction as a precursor of heme.
If the observed increase of glycine consumption in rapidly proliferating cancer cells has its basis in the need for heme biosynthesis, then mitochondrial serine hydroxymethyltransferase should be considered as a key target for the development of new chemotherapic agents
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