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131.
Costa-Neto CM Parreiras-E-Silva LT Ruller R Oliveira EB Miranda A Oliveira L Ward RJ 《Biochemical and biophysical research communications》2006,347(3):634-640
The eukaryotic translation initiation factor 5A (eIF5A) is a protein ubiquitously present in archaea and eukarya, which undergoes a unique two-step post-translational modification called hypusination. Several studies have shown that hypusination is essential for a variety of functional roles for eIF5A, including cell proliferation and synthesis of proteins involved in cell cycle control. Up to now neither a totally selective inhibitor of hypusination nor an inhibitor capable of directly binding to eIF5A has been reported in the literature. The discovery of such an inhibitor might be achieved by computer-aided drug design based on the 3D structure of the human eIF5A. In this study, we present a molecular model for the human eIF5A protein based on the crystal structure of the eIF5A from Leishmania brasiliensis, and compare the modeled conformation of the loop bearing the hypusination site with circular dichroism data obtained with a synthetic peptide of this loop. Furthermore, analysis of amino acid variability between different human eIF5A isoforms revealed peculiar structural characteristics that are of functional relevance. 相似文献
132.
Nitric oxide degradation by potato tuber mitochondria: evidence for the involvement of external NAD(P)H dehydrogenases 总被引:1,自引:0,他引:1
The mechanisms of nitric oxide (NO) synthesis in plants have been extensively investigated. NO degradation can be just as important as its synthesis in controlling steady-state levels of NO. Here, we examined NO degradation in mitochondria isolated from potato tubers and the contribution of the respiratory chain to this process. NO degradation was faster in mitochondria energized with NAD(P)H than with succinate or malate. Oxygen consumption and the inner membrane potential were transiently inhibited by NO in NAD(P)H-energized mitochondria, in contrast to the persistent inhibition seen with succinate. NO degradation was abolished by anoxia and superoxide dismutase, which suggested that NO was consumed by its reaction with superoxide anion (O2(-)). Antimycin-A stimulated and myxothiazol prevented NO consumption in succinate- and malate-energized mitochondria. Although favored by antimycin-A, NAD(P)H-mediated NO consumption was not abolished by myxothiazol, indicating that an additional site of O2(-) generation, besides complex III, stimulated NO degradation. Larger amounts of O2(-) were generated in NAD(P)H- compared to succinate- or malate-energized mitochondria. NAD(P)H-mediated NO degradation and O2(-) production were stimulated by free Ca2+ concentration. Together, these results indicate that Ca2+-dependent external NAD(P)H dehydrogenases, in addition to complex III, contribute to O2(-) production that favors NO degradation in potato tuber mitochondria. 相似文献
133.
134.
Santelmo Vasconcelos Gisele L. Nunes Mariana C. Dias Jamily Lorena Renato R. M. Oliveira Talvne G. L. Lima Eder S. Pires Rafael B. S. Valadares Ronnie Alves Maurício T. C. Watanabe Daniela C. Zappi Alice L. Hiura Mayara Pastore Liziane V. Vasconcelos Nara F. O. Mota Pedro L. Viana Andr S. B. Gil Andr O. Simes Vera L. ImperatrizFonseca Raymond M. Harley Ana M. Giulietti Guilherme Oliveira 《Ecology and evolution》2021,11(19):13348
The canga of the Serra dos Carajás, in Eastern Amazon, is home to a unique open plant community, harboring several endemic and rare species. Although a complete flora survey has been recently published, scarce to no genetic information is available for most plant species of the ironstone outcrops of the Serra dos Carajás. In this scenario, DNA barcoding appears as a fast and effective approach to assess the genetic diversity of the Serra dos Carajás flora, considering the growing need for robust biodiversity conservation planning in such an area with industrial mining activities. Thus, after testing eight different DNA barcode markers (matK, rbcL, rpoB, rpoC1, atpF‐atpH, psbK‐psbI, trnH‐psbA, and ITS2), we chose rbcL and ITS2 as the most suitable markers for a broad application in the regional flora. Here we describe DNA barcodes for 1,130 specimens of 538 species, 323 genera, and 115 families of vascular plants from a highly diverse flora in the Amazon basin, with a total of 344 species being barcoded for the first time. In addition, we assessed the potential of using DNA metabarcoding of bulk samples for surveying plant diversity in the canga. Upon achieving the first comprehensive DNA barcoding effort directed to a complete flora in the Brazilian Amazon, we discuss the relevance of our results to guide future conservation measures in the Serra dos Carajás. 相似文献
135.
The trophic structure of benthic communities in the Tagus estuary and adjacent coastal shelf was characterized according to
a functional guild approach, based on sampling surveys conducted between 1987 and 2000. Macrobenthic organisms were assigned
to seven distinct trophic groups (herbivorous, filter feeders, surface deposit feeders, subsurface deposit feeders, carnivores,
filter feeders/detritivores, carnivores/detritivores) and the dominance of these groups was related to environmental variables
using multivariate ordination techniques. Surface-deposit feeders were numerically dominant in the Tagus estuary, making up
52% of the benthic communities, while in the adjacent coastal shelf the assemblage was dominated by both surface-deposit feeders
and filter feeders (37% and 33%, respectively). When biomass was considered, filter feeders and filter feeders/detritivores
were the dominant groups in the estuary, while for the adjacent coastal shelf filter feeders represented 83% of the total
biomass. Salinity, depth and sediment composition were the main factors structuring spatial distribution. Surface-deposit
feeders were the most abundant macrobenthos of the upper estuary. Surface deposit feeders also dominated the middle and the
lower estuary but the proportion of filter feeders as well as other trophic groups increased with salinity. Generally, a more
even distribution of trophic structure was found at stations with high salinity. In the adjacent coastal shelf, the trophic
diversity decreased with depth. The trophic structure revealed that filter feeders dominated in abundance and biomass in shallow
sandy sediments (<25 m), while in deeper sandy mud and muddy habitats (>50 m to 260 m), deposit feeders and carnivores were
the most important groups in abundance and biomass, respectively. 相似文献
136.
137.
Mikovski Andréia Izabel da Silva Nayara Tayane Silva Lázara Aline Simões Machado Mariana de Souza Barbosa Lília Cristina Reis Aryane Campos de Matos Elyabe Monteiro Viccini Lyderson Facio da Silva Souza Claudinei Machado Marcelo Dias Otoni Wagner Campos de Carvalho Ilio Fealho Rocha Diego Ismael da Silva Maurecilne Lemes 《Plant Cell, Tissue and Organ Culture》2021,145(2):239-259
Plant Cell, Tissue and Organ Culture (PCTOC) - Somaclonal variation during in vitro culture is often an undesirable phenomenon but may also be a source of genetic variation useful for breeders. The... 相似文献
138.
Morales Quinones M Winston JT Stromhaug PE 《The Journal of biological chemistry》2012,287(13):10121-10133
Misfolded protein aggregation causes disease and aging; autophagy counteracts this by eliminating damaged components, enabling cells to survive starvation. The cytoplasm-to-vacuole targeting pathway in yeast encompasses the aggregation of the premature form of aminopeptidase 1 (prApe1) in cytosol and its sequestration by autophagic proteins into a vesicle for vacuolar transport. We show that the propeptide of Ape1 is important for aggregation and vesicle formation and that it is sufficient for binding to prApe1 and Atg19. Defective aggregation disrupts vacuolar transport, suggesting that aggregate shape is important in vesicle formation, whereas Atg19 binding is not sufficient for vacuolar transport. Aggregation involves hydrophobicity, whereas Atg19 binding requires additional electrostatic interactions. Ape1 dodecamerization may cluster propeptides into trimeric structures, with sufficient affinity to form propeptide hexamers by binding to other dodecamers, causing aggregation. We show that Ape1 aggregates bind Atg19 and Atg8 in vitro; this could be used as a scaffold for an in vitro assay of autophagosome formation to elucidate the mechanisms of autophagy. 相似文献
139.
The acyl coenzyme A (CoA) binding protein AcbA is cleaved to form a peptide (SDF-2) that coordinates spore encapsulation during the morphogenesis of Dictyostelium discoideum fruiting bodies. We present genetic evidence that the misspecification of cell types seen in mutants of the serine protease/ABC transporter TagA results from the loss of normal interactions with AcbA. Developmental phenotypes resulting from aberrant expression of the TagA protease domain, such as the formation of supernumerary tips on aggregates and the production of excess prestalk cells, are suppressed by null mutations in the acbA gene. Phenotypes resulting from the deletion of tagA, such as overexpression of the prestalk gene ecmB and the misexpression of the prespore gene cotB in stalk cells, are also observed in acbA mutants. Moreover, tagA- mutants fail to produce SDF-2 during fruiting body morphogenesis but are able to do so if they are stimulated with exogenous SDF-2. These results indicate that the developmental program depends on TagA and AcbA working in concert with each other during cell type differentiation and suggest that TagA is required for normal SDF-2 signaling during spore encapsulation. 相似文献