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1.
Survival of Male Patients with Incontinentia Pigmenti Carrying a Lethal Mutation Can Be Explained by Somatic Mosaicism or Klinefelter Syndrome 总被引:2,自引:0,他引:2
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The International IP Consortium 《American journal of human genetics》2001,69(6):1210-1217
Incontinentia pigmenti (IP), or "Bloch-Sulzberger syndrome," is an X-linked dominant disorder characterized by abnormalities of skin, teeth, hair, and eyes; skewed X-inactivation; and recurrent miscarriages of male fetuses. IP results from mutations in the gene for NF-kappaB essential modulator (NEMO), with deletion of exons 4-10 of NEMO accounting for >80% of new mutations. Male fetuses inheriting this mutation and other "null" mutations of NEMO usually die in utero. Less deleterious mutations can result in survival of males subjects, but with ectodermal dysplasia and immunodeficiency. Male patients with skin, dental, and ocular abnormalities typical of those seen in female patients with IP (without immunodeficiency) are rare. We investigated four male patients with clinical hallmarks of IP. All four were found to carry the deletion normally associated with male lethality in utero. Survival in one patient is explained by a 47,XXY karyotype and skewed X inactivation. Three other patients possess a normal 46,XY karyotype. We demonstrate that these patients have both wild-type and deleted copies of the NEMO gene and are therefore mosaic for the common mutation. Therefore, the repeat-mediated rearrangement leading to the common deletion does not require meiotic division. Hypomorphic alleles, a 47,XXY karyotype, and somatic mosaicism therefore represent three mechanisms for survival of males carrying a NEMO mutation. 相似文献
2.
Troganis A Gerothanassis IP Athanassiou Z Mavromoustakos T Hawkes GE Sakarellos C 《Biopolymers》2000,53(1):72-83
The cis/trans conformational equilibrium of the two Ac-Pro isomers of the beta-turn model dipeptide [13C]-Ac-L-Pro-D-Ala-NHMe, 98% 13C enriched at the acetyl carbonyl atom, was investigated by the use of variable temperature gradient enhanced 1H-nmr, two-dimensional (2D) 1H,1H nuclear Overhauser effect spectroscopy (NOESY), 13C,1H one-dimensional steady-state intermolecular NOE, and molecular dynamics calculations. The temperature dependence of the cis/trans Ala(NH) protons are in the region expected for random-coil peptides in H2O (delta delta/delta T = -9.0 and -8.9 ppb for the cis and trans isomers, respectively). The trans NH(CH3) proton indicates smaller temperature dependence (delta delta/delta T approximately -4.8 ppb) than that of the cis isomer (-7.5 ppb). 2D 1H,1H NOESY experiments at 273 K demonstrate significant NOEs between ProH alpha-AlaNH and AlaNH-NH(R) for the trans isomer. The experimental NOE data, coupled with computational analysis, can be interpreted by assuming that the trans isomer most likely adopts an ensemble of folded conformations. The C-CONH(CH3) fragment exhibits significant conformational flexibility; however, a low-energy conformer resembles closely the beta II-turn folded conformations of the x-ray structure of the related model peptide trans-BuCO-L-Pro-Me-D-Ala-NHMe. On the contrary, the cis isomer adopts open conformations. Steady-state intermolecular solute-solvent (H2O) 13C,1H NOE indicates that the water accessibility of the acetyl carbonyl carbons is nearly the same for both isomers. This is consistent with rapid fluctuations of the conformational ensemble and the absence of a highly shielded acetyl oxygen from the bulk solvent. Variable temperature 1H-nmr studies of the cis/trans conformational equilibrium indicate that the trans form is enthalpically favored (delta H degree = -5.14 kJ mole-1) and entropically (delta S degree = -5.47 J.K-1.mole-1) disfavored relative to the cis form. This demonstrates that, in the absence of strongly stabilizing sequence-specific interresidue interactions involving side chains and/or charged terminal groups, the thermodynamic difference of the cis/trans isomers is due to the combined effect of intramolecular and intermolecular (hydration) induced conformational changes. 相似文献
3.
Kalodimos CG Gerothanassis IP Pierattelli R Troganis A 《Journal of inorganic biochemistry》2000,79(1-4):371-380
13C, 17O and 57Fe NMR spectra of several carbonmonoxy hemoprotein models with varying polar and steric effects of the distal organic superstructure, constraints of the proximal side, and porphyrin ruffling are reported. Both heme models and heme proteins obey a similar excellent linear delta(13C) versus nu(C-O) relationship which is primarily due to modulation of pi-back-bonding from the Fe d(pi) to CO pi* orbital by the distal pocket polar interactions. The lack of correlation between delta(13C) and delta(17O) suggests that the two probes do not reflect a similar type of electronic and structural perturbation. delta(17O) is not primarily influenced by the local distal field interactions and does not correlate with any single structural property of the Fe-C-O unit; however, atropisomerism and deformation of the porphyrin geometry appear to play a significant role. 57Fe shieldings vary by nearly 900 ppm among various hemes and an excellent correlation was found between delta(57Fe) and the absolute crystallographic average displacement of the meso carbon atoms, /Cm/, relative to the porphyrin core mean plane. The excellent correlation between iron-57 shieldings and the average shieldings of the meso carbons of the porphyrin skeleton of TPP derivatives suggests that the two probes reflect a similar type of electronic and structural perturbation which is primarily porphyrin ruffling. 相似文献
4.
Identification of the major constituents of Hypericum perforatum by LC/SPE/NMR and/or LC/MS 总被引:1,自引:0,他引:1
Tatsis EC Boeren S Exarchou V Troganis AN Vervoort J Gerothanassis IP 《Phytochemistry》2007,68(3):383-393
The newly established hyphenated instrumentation of LC/DAD/SPE/NMR and LC/UV/(ESI)MS techniques have been applied for separation and structure verification of the major known constituents present in Greek Hypericum perforatum extracts. The chromatographic separation was performed on a C18 column. Acetonitrile-water was used as a mobile phase. For the on-line NMR detection, the analytes eluted from column were trapped one by one onto separate SPE cartridges, and hereafter transported into the NMR flow-cell. LC/DAD/SPE/NMR and LC/UV/MS allowed the characterization of constituents of Greek H. perforatum, mainly naphtodianthrones (hypericin, pseudohypericin, protohypericin, protopseudohypericin), phloroglucinols (hyperforin, adhyperforin), flavonoids (quercetin, quercitrin, isoquercitrin, hyperoside, astilbin, miquelianin, I3,II8-biapigenin) and phenolic acids (chlorogenic acid, 3-O-coumaroylquinic acid). Two phloroglucinols (hyperfirin and adhyperfirin) were detected for the first time, which have been previously reported to be precursors in the biosynthesis of hyperforin and adhyperforin. 相似文献
5.
Nagulapalli M Parigi G Yuan J Gsponer J Deraos G Bamm VV Harauz G Matsoukas J de Planque MR Gerothanassis IP Babu MM Luchinat C Tzakos AG 《Structure (London, England : 1993)》2012,20(3):522-533
Protein interactions within regulatory networks should adapt in a spatiotemporal-dependent dynamic environment, in order to process and respond to diverse and versatile cellular signals. However, the principles governing recognition pliability in protein complexes are not well understood. We have investigated a region of the intrinsically disordered protein myelin basic protein (MBP(145-165)) that interacts with calmodulin, but that also promiscuously binds other biomolecules (membranes, modifying enzymes). To characterize this interaction, we implemented an NMR spectroscopic approach that calculates, for each conformation of the complex, the maximum occurrence based on recorded pseudocontact shifts and residual dipolar couplings. We found that the MBP(145-165)-calmodulin interaction is characterized by structural heterogeneity. Quantitative comparative analysis indicated that distinct conformational landscapes of structural heterogeneity are sampled for different calmodulin-target complexes. Such structural heterogeneity in protein complexes could potentially explain the way that transient and promiscuous protein interactions are optimized and tuned in complex regulatory networks. 相似文献
6.
S. LUYSSAERT P. CIAIS S. L. PIAO E.‐D. SCHULZE M. JUNG S. ZAEHLE M. J. SCHELHAAS M. REICHSTEIN G. CHURKINA D. PAPALE G. ABRIL C. BEER J. GRACE D. LOUSTAU G. MATTEUCCI F. MAGNANI G. J. NABUURS H. VERBEECK M. SULKAVA G. R.
Van Der WERF I. A. JANSSENS members of the CARBOEUROPE‐IP SYNTHESIS TEAM 《Global Change Biology》2010,16(5):1429-1450
We present a new synthesis, based on a suite of complementary approaches, of the primary production and carbon sink in forests of the 25 member states of the European Union (EU‐25) during 1990–2005. Upscaled terrestrial observations and model‐based approaches agree within 25% on the mean net primary production (NPP) of forests, i.e. 520±75 g C m?2 yr?1 over a forest area of 1.32 × 106 km2 to 1.55 × 106 km2 (EU‐25). New estimates of the mean long‐term carbon forest sink (net biome production, NBP) of EU‐25 forests amounts 75±20 g C m?2 yr?1. The ratio of NBP to NPP is 0.15±0.05. Estimates of the fate of the carbon inputs via NPP in wood harvests, forest fires, losses to lakes and rivers and heterotrophic respiration remain uncertain, which explains the considerable uncertainty of NBP. Inventory‐based assessments and assumptions suggest that 29±15% of the NBP (i.e., 22 g C m?2 yr?1) is sequestered in the forest soil, but large uncertainty remains concerning the drivers and future of the soil organic carbon. The remaining 71±15% of the NBP (i.e., 53 g C m?2 yr?1) is realized as woody biomass increments. In the EU‐25, the relatively large forest NBP is thought to be the result of a sustained difference between NPP, which increased during the past decades, and carbon losses primarily by harvest and heterotrophic respiration, which increased less over the same period. 相似文献
7.
Nitrogen oxide-containing compounds displaced the peripheral benzodiazepine ligand [3H]Ro5-4864 from guinea pig membrane preparations. Sodium nitroprusside (SNP) was the most potent (IC50 = 5.61 ± 1.72 × 10−5 M). Moreover, its ability to bind to these receptors showed marked tissue variability (heart> kidney cerebral cortex). When tested on rat atrium, SNP by itself had no effect on basal inotropy or the increase in inotropy induced by (−)-S-BAY K 8644. In contrast, Ro5-4864 potentiated the marked increase in inotropy induced by (−)-S-Bay K 8644, and SNP completely abolished the potentiation of inotropy observed with Ro5-4864. Since peripheral benzodiazepine receptors are associated with calcium mobilization in the heart, these findings may indicate that some of the clinical effects of nitric oxide-generating drugs could be mediated by these receptors. 相似文献
8.
Dimitrios A. Diamantis Sarka Ramesova Christos M. Chatzigiannis Ilaria Degano Paraskevi S. Gerogianni Konstantina E. Karadima Sonia Perikleous Dimitrios Rekkas Ioannis P. Gerothanassis Dimitrios Galaris Thomas Mavromoustakos Georgia Valsami Romana Sokolova Andreas G. Tzakos 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(9):1913-1924
Background
Flavonoids possess a rich polypharmacological profile and their biological role is linked to their oxidation state protecting DNA from oxidative stress damage. However, their bioavailability is hampered due to their poor aqueous solubility. This can be surpassed through encapsulation to supramolecular carriers as cyclodextrin (CD). A quercetin- 2HP-β-CD complex has been formerly reported by us. However, once the flavonoid is in its 2HP-β-CD encapsulated state its oxidation potential, its decomplexation mechanism, its potential to protect DNA damage from oxidative stress remained elusive. To unveil this, an array of biophysical techniques was used.Methods
The quercetin-2HP-β-CD complex was evaluated through solubility and dissolution experiments, electrochemical and spectroelectrochemical studies (Cyclic Voltammetry), UV–Vis spectroscopy, HPLC-ESI-MS/MS and HPLC-DAD, fluorescence spectroscopy, NMR Spectroscopy, theoretical calculations (density functional theory (DFT)) and biological evaluation of the protection offered against H2O2-induced DNA damage.Results
Encapsulation of quercetin inside the supramolecule's cavity enhanced its solubility and retained its oxidation profile. Although the protective ability of the quercetin-2HP-β-CD complex against H2O2 was diminished, iron serves as a chemical stimulus to dissociate the complex and release quercetin.Conclusions
We found that in a quercetin-2HP-β-CD inclusion complex quercetin retains its oxidation profile similarly to its native state, while iron can operate as a chemical stimulus to release quercetin from its host cavity.General significance
The oxidation profile of a natural product once it is encapsulated in a supramolecular carrier was unveiled as also it was discovered that decomplexation can be triggered by a chemical stimilus. 相似文献9.
Nucleotide sequence of the genes for tryptophan synthase in Pseudomonas aeruginosa 总被引:17,自引:0,他引:17
We have determined the DNA sequence of the two adjacent genes for the alpha
and beta chains of tryptophan synthase in Pseudomonas aeruginosa, along
with 34 5'-flanking and 799 3'-flanking base pairs. The gene order is trpBA
as predicted from earlier genetic studies, and the two cistrons overlap by
4 bp; a ribosome binding site for the second gene is evident in the coding
sequence of the first gene. We have also determined the location of three
large deletions eliminating portions of each gene. A detailed comparison of
the deduced P. aeruginosa amino acid sequence with those published for E.
coli, Bacillus subtilis, and Saccharomyces cerevisiae shows much similarity
throughout the beta and most of the alpha subunit. Most of the residues
implicated by chemical modification or mutation as being critical for
enzymatic activity are conserved, along with many others, suggesting that
three-dimensional structure has remained largely constant during evolution.
We also report the construction of a recombinant plasmid that overproduces
a slightly modified alpha subunit from P. aeruginosa that can form a
functionally effective multimer with normal E. coli beta 2 subunit in vivo.
相似文献
10.