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1.
bioRxiv ; 2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38645137

RESUMO

Alpha-synuclein (αsyn) is an intrinsically disordered protein that aggregates in the brain in several neurodegenerative diseases collectively called synucleinopathies. Phosphorylation of αsyn at serine 129 (PSER129) was considered rare in the healthy human brain but is enriched in pathological αsyn aggregates and is used as a specific marker for disease inclusions. However, recent observations challenge this assumption by demonstrating that PSER129 results from neuronal activity and can be readily detected in the non-diseased mammalian brain. Here, we investigated experimental conditions under which two distinct PSER129 pools, namely endogenous-PSER129 and aggregated-PSER129, could be detected and differentiated in the mammalian brain. Results showed that in the wild-type (WT) mouse brain, perfusion fixation conditions greatly influenced the detection of endogenous-PSER129, with endogenous-PSER129 being nearly undetectable after delayed perfusion fixation (30-minute and 1-hour postmortem interval). Exposure to anesthetics (e.g., Ketamine or xylazine) before perfusion did not significantly influence endogenous-PSER129 detection or levels. In situ, non-specific phosphatase calf alkaline phosphatase (CIAP) selectively dephosphorylated endogenous-PSER129 while αsyn preformed fibril (PFF)-seeded aggregates and genuine disease aggregates (Lewy pathology and Papp-Lantos bodies in Parkinson's disease and multiple systems atrophy brain, respectively) were resistant to CIAP-mediated dephosphorylation. The phosphatase resistance of aggregates was abolished by sample denaturation, and CIAP-resistant PSER129 was closely associated with proteinase K (PK)-resistant αsyn (i.e., a marker of aggregation). CIAP pretreatment allowed for highly specific detection of seeded αsyn aggregates in a mouse model that accumulates non-aggregated-PSER129. We conclude that αsyn aggregates are impervious to phosphatases, and CIAP pretreatment increases detection specificity for aggregated-PSER129, particularly in well-preserved biological samples (e.g., perfusion fixed or flash-frozen mammalian tissues) where there is a high probability of interference from endogenous-PSER129. Our findings have important implications for the mechanism of PSER129-accumulation in the synucleinopathy brain and provide a simple experimental method to differentiate endogenous-from aggregated PSER129.

2.
Curr Opin Struct Biol ; 44: 201-210, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-28575754

RESUMO

Proteins effect a number of biological functions, from cellular signaling, organization, mobility, and transport to catalyzing biochemical reactions and coordinating an immune response. These varied functions are often dependent upon macromolecular interactions, particularly with other proteins. Small-scale studies in the scientific literature report protein-protein interactions (PPIs), but slowly and with bias towards well-studied proteins. In an era where genomic sequence is readily available, deducing genotype-phenotype relationships requires an understanding of protein connectivity at proteome-scale. A proteome-scale map of the protein-protein interaction network provides a global view of cellular organization and function. Here, we discuss a summary of methods for building proteome-scale interactome maps and the current status and implications of mapping achievements. Not only do interactome maps serve as a reference, detailing global cellular function and organization patterns, but they can also reveal the mechanisms altered by disease alleles, highlight the patterns of interaction rewiring across evolution, and help pinpoint biologically and therapeutically relevant proteins. Despite the considerable strides made in proteome-wide mapping, several technical challenges persist. Therefore, future considerations that impact current mapping efforts are also discussed.


Assuntos
Modelos Moleculares , Mapeamento de Interação de Proteínas/métodos , Proteômica/métodos , Simulação por Computador , Humanos
3.
Int J Lab Hematol ; 37(6): 869-75, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26332422

RESUMO

INTRODUCTION: The Sysmex XN modular system (Sysmex, Kobe, Japan) uses a novel technology for white blood cell (WBC) count and differential, using separate channels: white cell nucleated (WNR), WBC differential (WDF), and white progenitor cell (WPC) channels. We questioned how concordant WBC counts would be between them. METHODS: In a total of 6327 consecutive specimens, WBC counts were compared between WNR and WDF channels. They were also compared in three groups of WBC counts and two groups of chemotherapy status. In 508 specimens from the 4361 specimens that were run on the XN-20 module, the WPC channel was used for reflex test. Data were compared using Pearson's correlation, absolute difference, and percent difference (%D). RESULTS: WBC counts between WNR and WDF channels showed very high correlations in total specimens (r = 0.9976) and in the groups of WBC counts and chemotherapy. As WBC count increased, absolute difference increased, while %D decreased (P < 0.0001, both). Percent difference was 1.55% in total specimens and showed the highest value in the severe leukopenia group (<1.0 × 10(9)/L, 6.18%). CONCLUSIONS: This is the first large-scale study on novel channel technology for WBC counts in the Sysmex XN. WBC counts by WNR, WDF, and WPC channels are highly correlated, and they are overall interchangeable and reliable.


Assuntos
Células-Tronco Hematopoéticas , Contagem de Leucócitos/métodos , Leucócitos Mononucleares , Leucócitos , Humanos , Contagem de Leucócitos/instrumentação , Contagem de Leucócitos/normas , Leucócitos/citologia , Leucócitos/metabolismo , Leucócitos Mononucleares/citologia , Leucócitos Mononucleares/metabolismo , Reprodutibilidade dos Testes
4.
Int J Lab Hematol ; 35(6): 658-65, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23738834

RESUMO

INTRODUCTION: Cord blood (CB) is an important source of hematopoietic stem cells and reflects the hematologic status of neonates. ABX Pentra DX 120 (Horiba Medical, Montpellier, France) and Sysmex XE-2100 (Sysmex, Kobe, Japan) were compared in 200 CB specimens. METHODS: Complete blood count parameters including white blood cell (WBC) differential counts were compared between the two analyzers. Double differential matrix (DDX) by ABX Pentra DX 120 and hematopoietic progenitor cell (HPC) by Sysmex XE-2100 were compared with CD34(+) cells by flow cytometry. RESULTS: Most of the parameters showed acceptable correlation between the two analyzers. Although WBC differential of both analyzers showed acceptable correlation with manual counts, mononuclear cells (MNC) by ABX Pentra DX 120 better correlated with manual count than MNC by Sysmex XE-2100. NRBC by Sysmex XE-2100 better correlated with manual count than NRBC by ABX Pentra DX 120. ABX Pentra DX 120 showed better flagging performances. DDX better correlated with CD34(+) cells than HPC. CONCLUSION: Although the results from both analyzers are mostly interchangeable and reliable in CB specimens, flagging performance of ABX Pentra DX 120 seems to be superior to that of Sysmex XE-2100. DDX by ABX Pentra DX 120 would be valuable to evaluate the quality of CB for further therapeutic utilization.


Assuntos
Antígenos CD34/metabolismo , Sangue Fetal/citologia , Citometria de Fluxo/instrumentação , Citometria de Fluxo/normas , Adulto , Contagem de Células Sanguíneas/instrumentação , Contagem de Células Sanguíneas/métodos , Contagem de Células Sanguíneas/normas , Feminino , Citometria de Fluxo/métodos , Células-Tronco Hematopoéticas/metabolismo , Humanos , Recém-Nascido , Pessoa de Meia-Idade , Adulto Jovem
5.
Int J Lab Hematol ; 35(5): 528-33, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23286350

RESUMO

INTRODUCTION: Immature platelet fraction (IPF) is a parameter for reticulated platelets. A high percentage IPF (%-IPF) is indicative of consumptive or recovering thrombocytopenic disorders in contrast to a low %-IPF seen in aplastic states. Absolute IPF (A-IPF) specifically reflects the number of immature platelets in circulation. This study aimed to establish reliable reference intervals for %-IPF and A-IPF. METHODS: Except outliers, platelet counts and IPF were determined in 2152 healthy individuals (1252 men and 900 women) and 133 umbilical cord blood from healthy full-term neonates using XE-2100 hematology analyzer (Sysmex, Kobe, Japan). The reference intervals for %-IPF and A-IPF were defined using nonparametrical percentile methods according to the Clinical and Laboratory Standard Institute (CLSI) guideline. RESULTS: Platelets,%-IPF, and A-IPF all showed nonparametrical distributions. In total individuals, the reference intervals for %-IPF and A-IPF were 0.5-3.3% (0.5-3.1% in men; 0.5-3.4% in women) and 1.25-7.02 × 10(9) /L (1.30-6.80 × 10(9) /L in men; 1.21-7.15 × 10(9) /L in women), respectively. The reference intervals for %-IPF and A-IPF in umbilical cord blood were 0.7-3.8% and 1.93-9.7 × 10(9) /L, respectively. CONCLUSIONS: This study provides the reference interval for IPF, including %-IPF and A-IPF, according to the CLSI guideline. These results could be used as fundamental data for clinical use as well as future researches.


Assuntos
Plaquetas/citologia , Contagem de Plaquetas/normas , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Contagem de Plaquetas/métodos , Valores de Referência , Trombocitopenia/sangue , Trombocitopenia/diagnóstico , Adulto Jovem
7.
J Food Sci ; 73(2): H28-32, 2008 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-18298733

RESUMO

Banana, orange, and apple are the major fruits in Western and Asian diets. In order to find the effects of these fruits, neuron like PC12 cells were exposed to the extracts of these fruits before H(2)O(2) treatment. We found a significant viability of PC12 cells by the MTT reduction test, which indicated that the phenolics of banana, orange, and apple fruits prevented oxidative stress-induced neurotoxicity. Additional tests by lactate dehydrogenase and trypan blue exclusion assays showed that the extracts reduced oxidative stress-induced neuronal cell membrane damage. These results suggest that fresh apples, banana, and orange in our daily diet along with other fruits may protect neuron cells against oxidative stress-induced neurotoxicity and may play an important role in reducing the risk of neurodegenerative disorders such as Alzheimer's disease.


Assuntos
Citrus sinensis/química , Malus/química , Musa/química , Degeneração Neural/etiologia , Estresse Oxidativo/efeitos dos fármacos , Animais , Sobrevivência Celular , Humanos , Peróxido de Hidrogênio , Neurônios/efeitos dos fármacos , Neurônios/fisiologia , Células PC12 , Ratos
8.
Genes Dev ; 15(4): 455-66, 2001 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-11230153

RESUMO

Hepatitis B, one of the most common infectious diseases in the world, is closely associated with acute and chronic hepatitis, cirrhosis, and hepatocellular carcinoma. Many clinical investigations have revealed that hepatic fibrosis is an important component of these liver diseases caused by chronic hepatitis B. TGF-beta signaling plays an important role in the pathogenesis of fibrosis in chronic hepatitis and cirrhosis. As these diseases are associated with hepatitis B virus (HBV) infection, we examined the possibility that the HBV-encoded pX oncoprotein regulates TGF-beta signaling. We show that pX enhances transcriptional activity in response to TGF-beta, BMP-2, and activin by stabilizing the complex of Smad4 with components of the basic transcriptional machinery. Additionally, confocal microscopic studies suggest that pX facilitates and potentiates the nuclear translocation of Smads, further enhancing TGF-beta signaling. Our studies suggest a new paradigm for amplification of Smad-mediated signaling by an oncoprotein and suggest that enhanced Smad-mediated signaling may contribute to HBV-associated liver fibrosis.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Vírus da Hepatite B/genética , Cirrose Hepática/virologia , Proteínas Oncogênicas Virais/fisiologia , Transdução de Sinais/fisiologia , Transativadores/metabolismo , Fator de Crescimento Transformador beta/metabolismo , Células 3T3 , Animais , Núcleo Celular/metabolismo , Vírus da Hepatite B/patogenicidade , Camundongos , Proteínas Oncogênicas Virais/genética , Proteínas Oncogênicas Virais/metabolismo , Ligação Proteica , Proteína Smad4 , Ativação Transcricional
9.
Oncogene ; 19(1): 151-4, 2000 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-10644990

RESUMO

The epithelium-specific transcription factor, ERT/ESX/ESE-1/ELF3, binds to the TGF-beta RII promoter in a sequence specific manner and regulates its expression. In this study, we investigated whether ERT could regulate endogenous TGF-beta RII expression in Hs578t breast cancer cells. Analyses of the Hs578t parental cell line revealed low RII mRNA expression and resistance to the growth inhibitory effects of TGF-beta. Infection of this cell line with a retroviral construct expressing ERT induced higher levels of endogenous RII mRNA expression and protein expression relative to cells infected with chloramphenicol acetyltransferase (CATneo) as a control. Relative to control cells, the ERTneo-expressing Hs578t cells show approximately a 50% reduction in cell growth in the presence of exogenous TGF-beta1, as well as a fourfold higher induction of activation in transient transfection assays using the 3TP-luciferase reporter construct. When transplanted into athymic mice, ERT-expressing Hs578t cells showed decreased and delayed tumorigenicity compared with control cells. This data strongly suggests that ERT plays an important role as a transcriptional activator of TGF-beta RII expression, and that deregulated ERT expression may play a critical role in rendering Hs578t human breast cancer cells insensitive to TGF-beta's growth inhibitory effects.


Assuntos
Neoplasias da Mama/tratamento farmacológico , Proteínas de Ligação a DNA , Proteínas Proto-Oncogênicas/fisiologia , Receptores de Fatores de Crescimento Transformadores beta/genética , Transativadores/fisiologia , Fatores de Transcrição/fisiologia , Fator de Crescimento Transformador beta/farmacologia , Animais , Neoplasias da Mama/patologia , Feminino , Humanos , Camundongos , Camundongos Nus , Proteínas Serina-Treonina Quinases , Proteínas Proto-Oncogênicas c-ets , Receptor do Fator de Crescimento Transformador beta Tipo II
10.
Acta Neurochir (Wien) ; 142(11): 1263-73; discussion 1273-4, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-11201642

RESUMO

A co-operative study was conducted to determine the clinical characteristics of patients with moyamoya disease who were diagnosed and treated at neurosurgical institutes in Korea before 1995. Twenty-six hospitals contributed 505 cases and among them, the clinical characteristics of 334 patients with definite moyamoya disease were evaluated. The number of patients began to increase from the late 1980s, and after that approximately 20 patients were treated each year. There were two age peaks: from six to 15 and from 31 to 40 years of age. Haemorrhagic manifestations occurred in approximately 43% of the patients. The major clinical manifestations were haemorrhage in adults (62.4%) and ischaemia in children (61.2%). Overall 54.5% of the patients experienced decreased consciousness levels, mainly due to intracranial haemorrhage or cerebral infarction. In the patients with ischemic manifestations, the adult patients were more likely to have cerebral infarction than the pediatric patients (80% vs. 39%) and the pediatric patients were more likely to have TIA (61% vs. 25%). Thirty eight percent of the patients underwent bypass surgery and 53% of these procedures were performed bilaterally. Treatment policies, including indications for bypass surgery and commonly used drugs, were somewhat different according to the institution. Overall favorable outcome was 73%, and the most significant factor affecting poor outcome was haemorrhagic manifestation. This article describes the characteristics of 334 patients with moyamoya disease, who were diagnosed and treated at neurosurgical institutes in Korea before 1995.


Assuntos
Revascularização Cerebral/métodos , Doença de Moyamoya/patologia , Adolescente , Adulto , Idade de Início , Idoso , Isquemia Encefálica/etiologia , Infarto Cerebral/etiologia , Criança , Pré-Escolar , Feminino , Humanos , Incidência , Lactente , Hemorragias Intracranianas/etiologia , Coreia (Geográfico)/epidemiologia , Masculino , Pessoa de Meia-Idade , Doença de Moyamoya/epidemiologia , Doença de Moyamoya/cirurgia , Prognóstico , Estudos Retrospectivos
11.
Nat Genet ; 23(2): 222-7, 1999 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-10508522

RESUMO

Chromosomal translocations resulting in the expression of chimaeric transcription factors are frequently observed in tumour cells, and have been suggested to be a common mechanism in human carcinogenesis. Ewing sarcoma and related peripheral primitive neuroectodermal tumours share recurrent translocations that fuse the gene EWSR1 (formerly EWS) from 22q-12 to FLI1 and genes encoding other ETS transcription factors (which bind DNA through the conserved ETS domain). It has been shown that transduction of the gene EWSR1-FLI1 (encoding EWS-FLI1 protein) can transform NIH3T3 cells, and that mutants containing a deletion in either the EWS domain or the DNA-binding domain in FLI1 lose this ability. This indicates that the EWS-FLI1 fusion protein may act as an aberrant transcription factor, but the exact mechanism of oncogenesis remains unknown. Because ETS transcription factors regulate expression of TGFBR2 (encoding the TGF-beta type II receptor, TGF-beta RII; Refs 9,14), a putative tumour suppressor gene, we hypothesized that TGFBR2 may be a target of the EWS-FLI1 fusion protein. We show here that Ewing sarcoma [corrected] (ES) cell lines with the EWSR1-FLI1 fusion have reduced TGF-beta sensitivity, and that fusion-positive ES cells and primary tumours both express low or undetectable levels of TGFBR2 mRNA and protein product. Co-transfection of FLI1 and the TGFBR2 promoter induces promoter activity, whereas EWSR1-FLI1 leads to suppression of TGFBR2 promoter activity and FLI1-induced promoter activity. Introduction of EWSR1-FLI1 into cells lacking the EWSR1-FLI1 fusion suppresses TGF-beta RII expression, whereas antisense to EWSR1-FLI1 in ES cell lines positive for this gene fusion restores TGF-beta RII expression. Furthermore, introduction of normal TGF-beta RII into ES cell lines restores TGF-beta sensitivity and blocks tumorigenicity. Our results implicate TGF-beta RII as a direct target of EWS-FLI1.


Assuntos
Proteínas de Fusão Oncogênica/fisiologia , Proteínas Proto-Oncogênicas , Receptores de Fatores de Crescimento Transformadores beta/genética , Fatores de Transcrição/fisiologia , Animais , Linhagem Celular , Proteínas de Ligação a DNA/genética , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Imuno-Histoquímica , Luciferases/genética , Luciferases/metabolismo , Camundongos , Camundongos Nus , Neuroblastoma/genética , Neuroblastoma/metabolismo , Neuroblastoma/patologia , Proteínas de Fusão Oncogênica/genética , Regiões Promotoras Genéticas/genética , Proteínas Serina-Treonina Quinases , Proteína Proto-Oncogênica c-fli-1 , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteína EWS de Ligação a RNA , Receptor do Fator de Crescimento Transformador beta Tipo II , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Sarcoma de Ewing/genética , Sarcoma de Ewing/metabolismo , Sarcoma de Ewing/patologia , Deleção de Sequência , Transativadores/genética , Fatores de Transcrição/genética , Transfecção , Fator de Crescimento Transformador beta/farmacologia , Células Tumorais Cultivadas/efeitos dos fármacos , Células Tumorais Cultivadas/metabolismo
12.
Arch Pharm Res ; 22(1): 1-8, 1999 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10071951

RESUMO

Transforming growth factor-beta (TGF-beta) is the prototypical multifunctional cytokine, participating in the regulation of vital cellular activities such as proliferation and differentiation as well as a number of basic physiological functions. The effects of TGF-beta are critically dependent on the expression and distribution of a family of TGF-beta receptors, the TGF-beta types I, II, and III. It is now known that a wide variety of human pathology can be caused by aberrant expression and function of these receptors. The coding sequence of the type II receptor (RII) appears to render it uniquely susceptible to DNA replication errors in the course of normal cell division. By virtue of its key role in the regulation of cell proliferation, TGF-beta RII should be considered as a tumor suppressor gene. High levels of mutation in the TGF-beta RII gene have been observed in a wide range of primarily epithelial malignancies, including colon and gastric cancer. It appears likely that mutation of the TGF-beta RII gene may be a very critical step in the pathway of carcinogenesis.


Assuntos
Neoplasias/metabolismo , Fator de Crescimento Transformador beta/fisiologia , Animais , Progressão da Doença , Receptores ErbB/metabolismo , Receptores ErbB/fisiologia , Humanos , Mutação , Neoplasias/patologia , Fator de Crescimento Transformador beta/genética , Fator de Crescimento Transformador beta/metabolismo
13.
J Biol Chem ; 273(50): 33750-8, 1998 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-9837963

RESUMO

We have explored the regulation of transforming growth factor beta (TGF-beta) activity in tissue repair by examining the interactions of Zf9/core promoter-binding protein, a Kruppel-like zinc finger transcription factor induced early in hepatic stellate cell (HSC) activation, with promoters for TGF-beta1 and TGF-beta receptors, types I and II. Nuclear extracts from culture-activated HSCs bound avidly by electrophoretic mobility shift assay to two tandem GC boxes within the TGF-beta1 promoter but minimally to a single GC box; these results correlated with transactivation by Zf9 of TGF-beta1 promoter-reporters. Zf9 transactivated the full-length TGF-beta1 promoter in either primary HSCs, HSC-T6 cells (an SV40-immortalized rat HSC line), Hep G2 cells, or Drosophila Schneider (S2) cells. Recombinant Zf9-GST also bound to GC box sequences within the promoters for the types I and II TGF-beta receptors. Both type I and type II TGF-beta receptor promoters were also transactivated by Zf9 in mammalian cells but not in S2 cells. In contrast, Sp1 significantly transactivated both receptor promoters in S2 cells. These results suggest that (a) Zf9/core promoter-binding protein may enhance TGF-beta activity through transactivation of both the TGF-beta1 gene and its key signaling receptors, and (b) transactivating potential of Zf9 and Sp1 toward promoters for TGF-beta1 and its receptors are not identical and depend on the cellular context.


Assuntos
Fibrinogênio/biossíntese , Receptores de Fatores de Crescimento Transformadores beta/genética , Transativadores/metabolismo , Ativação Transcricional , Fator de Crescimento Transformador beta/genética , Animais , Núcleo Celular/metabolismo , Fígado/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley , Proteínas Recombinantes/metabolismo
14.
J Biol Chem ; 273(1): 110-7, 1998 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-9417054

RESUMO

A 2.5-kilobase cDNA clone that encodes a 371-amino acid novel transcription factor was isolated from a human placenta cDNA library using a yeast one-hybrid system. The novel ets-related transcription factor (ERT) showed a homology with the ETS DNA-binding domain. Using constructs of the transforming growth factor-beta (TGF-beta) type II receptor (RII) promoter linked to the luciferase gene, we have demonstrated that ERT activates transcription of the TGF-beta RII gene through the 5'-TTTCCTGTTTCC-3' response element spanning nucleotides +13 to +24 and multiple additional ETS binding sites between -1816 and -82 of the TGF-beta RII promoter. A specific interaction between ERT and the ETS binding sites was also demonstrated using an electrophoretic mobility shift assay. Deletion mapping of ERT protein suggests that the transactivation domain resides in the amino terminus while the DNA-binding domain is localized to the carboxyl-terminal region. Our results suggest that ERT might be a major transcription factor involved in the transcriptional regulation of the TGF-beta RII gene.


Assuntos
Regulação da Expressão Gênica , Proteínas Proto-Oncogênicas/metabolismo , Receptores de Fatores de Crescimento Transformadores beta/genética , Fatores de Transcrição/metabolismo , Clonagem Molecular , DNA Complementar , Humanos , Dados de Sequência Molecular , Regiões Promotoras Genéticas , Ligação Proteica , Proteínas Serina-Treonina Quinases , Proteínas Proto-Oncogênicas c-ets , Receptor do Fator de Crescimento Transformador beta Tipo II , Transcrição Gênica
15.
J Biol Chem ; 270(47): 28177-82, 1995 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-7499309

RESUMO

The urea-induced unfolding of the Escherichia coli tryptophan synthase alpha-subunit is examined via fluorescence measurements with tryptophan-containing alpha-subunit mutants, constructed by in vitro mutagenesis. Early unfolding studies with urea and guanidine suggested that the wild type protein unfolded in a two-step process with a stable intermediate composed of a native alpha-1 folding unit (residues 1-188) and a completely unfolded alpha-2 folding unit (residues 189-268). Recently, more detailed spectroscopic and calorimetric data from the Matthews and Yutani groups indicate that such a structure for the intermediates seems unlikely. Previously, we described the introduction of Trp residues as unfolding reporter groups separately into each of the folding domains and showed that these proteins are wild type enzymatically and in their stability to urea. The unfolding behavior of these alpha-subunits, monitored by fluorescence intensity changes at the discrete emission lambda max for each, in both equilibrium and kinetic experiments, suggest that: (a) both folding units commence unfolding simultaneously (near 2 M urea); (b) the larger alpha-1 unit unfolds in a multistep process, initially yielding a partially unfolded intermediate form which subsequently appears to unfold progressively to completion; and (c) the smaller alpha-2 unit unfolds in a single step event. These results are also clearly incompatible with the early proposals on the structure of the intermediate. It is suggested here that the intermediate is heterogeneous, consisting of a stable, partially unfolded form of alpha-1 attached to either a completely folded or completely unfolded form of alpha-2. These results are consistent with and provide an added dimension to the recent description of the proposed structure of the intermediate.


Assuntos
Escherichia coli/enzimologia , Triptofano Sintase/química , Triptofano , Calorimetria , Cinética , Medições Luminescentes , Substâncias Macromoleculares , Modelos Estruturais , Mutagênese Sítio-Dirigida , Mutação Puntual , Desnaturação Proteica , Dobramento de Proteína , Proteínas Recombinantes/química , Proteínas Recombinantes/efeitos dos fármacos , Proteínas Recombinantes/isolamento & purificação , Espectrometria de Fluorescência , Triptofano Sintase/efeitos dos fármacos , Triptofano Sintase/isolamento & purificação , Ureia/farmacologia
16.
J Biol Chem ; 270(30): 17712-5, 1995 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-7629069

RESUMO

Early studies suggested that the Escherichia coli tryptophan synthase alpha-subunit unfolded in a two-step process in which there was a stable intermediate composed of a native alpha-1 folding unit (residues 1-188) and a completely unfolded alpha-2 folding unit (residues 189-268). More recent evidence has indicated that such a structure for the intermediate seems unlikely. In this report, single Trp residues (absent in the wild-type alpha-subunit) are substituted separately for Phe residues at positions 139 (in alpha-1) and 258 (in alpha-2) to produce the F139W, F258W, and F139W/F258W mutant alpha-subunits. The UV absorbance and fluorescence properties of the F139W/F258W double mutant are identical with those of equimolar mixtures of the single mutants, suggesting that the Trp residue at each position can independently report the behavior of its respective folding unit. Each mutant alpha-subunit is wild-type enzymatically, and when UV absorbance is monitored, the urea-induced unfolding of the three tryptophan-containing alpha-subunits is virtually identical to the wild-type protein. These wild-type properties make these proteins attractive candidates for a fluorescence examination of the behavior of the individual folding units and the structure of potential intermediate(s) and as host proteins for the insertion of our existing destabilizing and/or stabilizing mutational alterations.


Assuntos
Escherichia coli/enzimologia , Triptofano Sintase/química , Triptofano/química , Ureia/química , Sequência de Bases , Estabilidade Enzimática , Dados de Sequência Molecular , Oligodesoxirribonucleotídeos , Dobramento de Proteína , Termodinâmica , Triptofano Sintase/metabolismo
17.
Ingu munje nonjip ; 2: 145-77, 1970.
Artigo em Inglês | MEDLINE | ID: mdl-12222506

RESUMO

PIP: To understand the effects of vasectomy on men, 1080 men were interviewed an average of 3.7 years after having had this operation. These men were grouped according to whether they privately paid for their operation or received it through a government program. The average age of these subjects was 37.8 years, and they had an average of 4.7 children. Reasons for vasectomy included economic considerations and the desire to limit their family. This type of operation was selected due to its permanance and reliability. Many men were motivated by family counselors or by the mass media. 68% had discussed the operation with their wives. 16% of the men had fears of impotence after the operation. Most were operated under a local anesthesia, and were not hospitalized. 57% did not bother to stay at home in recovery. Pain was encountered by 25% during the operation. Sexual activity was resumed in 3 weeks, with little change reported in eating or sleeping habits. Coital frequency decreased from 1.92-1.70 times/week. 90% of the men said they would recommend the operation to others.^ieng


Assuntos
Fatores Etários , Anticoncepção , Motivação , Dor , Paridade , Aceitação pelo Paciente de Cuidados de Saúde , Psicologia , Religião , Pesquisa , Comportamento Sexual , Classe Social , Esterilização Reprodutiva , Vasectomia , Atitude , Comportamento , Coeficiente de Natalidade , Comportamento Contraceptivo , Demografia , Doença , Economia , Serviços de Planejamento Familiar , Honorários e Preços , Fertilidade , Seguimentos , Instalações de Saúde , Planejamento em Saúde , Coreia (Geográfico) , População , Características da População , Dinâmica Populacional , Sinais e Sintomas , Fatores Socioeconômicos
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