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1.
Clin Immunol ; 256: 109795, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37769786

RESUMO

Celiac disease (CeD) is an autoimmune disorder affecting the small intestine with gluten as disease trigger. Infections including Influenza A, increase the CeD risk. While gluten-specific CD4+ T-cells, recognizing HLA-DQ2/DQ8 presented gluten-peptides, initiate and sustain the celiac immune response, CD8+ α/ß intraepithelial T-cells elicit mucosal damage. Here, we subjected TCRs from a cohort of 56 CeD patients and 22 controls to an analysis employing 749 published CeD-related TCRß-rearrangements derived from gluten-specific CD4+ T-cells and gluten-triggered peripheral blood CD8+ T-cells. We show, that in addition to TCRs from gluten-specific CD4+ T-cells, TCRs of gluten-triggered CD8+ T-cells are significantly enriched in CeD duodenal tissue samples. TCRß-rearrangements of gluten-triggered CD8+ T-cells were even more expanded in patients than TCRs from gluten-specific CD4+ T-cells (p < 0.0002) and highest in refractory CeD. Sequence alignments with TCR-antigen databases suggest that a subgroup of these most likely indirectly gluten-triggered TCRs recognize microbial, viral, and autoantigens.


Assuntos
Doença Celíaca , Humanos , Glutens , Linfócitos T CD8-Positivos , Receptores de Antígenos de Linfócitos T alfa-beta , Receptores de Antígenos de Linfócitos T
2.
Sci Rep ; 10(1): 10024, 2020 06 22.
Artigo em Inglês | MEDLINE | ID: mdl-32572036

RESUMO

T-cell receptor gene beta (TCRß) gene rearrangement represents a complex, tightly regulated molecular mechanism involving excision, deletion and recombination of DNA during T-cell development. RUNX1, a well-known transcription factor for T-cell differentiation, has recently been described to act in addition as a recombinase cofactor for TCRδ gene rearrangements. In this work we employed a RUNX1 knock-out mouse model and demonstrate by deep TCRß sequencing, immunostaining and chromatin immunoprecipitation that RUNX1 binds to the initiation site of TCRß rearrangement and its homozygous inactivation induces severe structural changes of the rearranged TCRß gene, whereas heterozygous inactivation has almost no impact. To compare the mouse model results to the situation in Acute Lymphoblastic Leukemia (ALL) we analyzed TCRß gene rearrangements in T-ALL samples harboring heterozygous Runx1 mutations. Comparable to the Runx1+/- mouse model, heterozygous Runx1 mutations in T-ALL patients displayed no detectable impact on TCRß rearrangements. Furthermore, we reanalyzed published sequence data from recurrent deletion borders of ALL patients carrying an ETV6-RUNX1 translocation. RUNX1 motifs were significantly overrepresented at the deletion ends arguing for a role of RUNX1 in the deletion mechanism. Collectively, our data imply a role of RUNX1 as recombinase cofactor for both physiological and aberrant deletions.


Assuntos
Subunidade alfa 2 de Fator de Ligação ao Core/fisiologia , Deleção de Genes , Rearranjo Gênico da Cadeia beta dos Receptores de Antígenos dos Linfócitos T/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Proteínas Proto-Oncogênicas c-ets/genética , Receptores de Antígenos de Linfócitos T alfa-beta/genética , Proteínas Repressoras/genética , Animais , Linfócitos B , Subunidade alfa 2 de Fator de Ligação ao Core/genética , Contagem de Linfócitos , Camundongos Knockout , Linfócitos T , Timo/patologia , Variante 6 da Proteína do Fator de Translocação ETS
3.
Acute Med ; 17(3): 124-129, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30129944

RESUMO

BACKGROUND: Early detection of vulnerable older adults at the emergency department (ED) and implementation of targeted interventions to prevent functional decline may lead to better patient outcomes. OBJECTIVE: To assess the level of agreement between four frequently used screening instruments: ISAR-HP, VMS, InterRAI ED Screener and APOP. METHODS: Observational prospective cohort study in patients ≥ 70 years attending Dutch ED. RESULTS: The prevalence of vulnerability ranged from 19% (APOP) to 45% (ISAR-HP). Overall there was a moderate agreement between the screening instruments (Fleiss Kappa of 0.42 (p<0.001)). CONCLUSION: Depending on the screening instrument used, either only a small percentage or almost as many as half of the presenting patients will be eligible for targeted interventions, leading to large dissimilarities in working processes, resources and costs.

4.
Heredity (Edinb) ; 117(3): 184-90, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27381323

RESUMO

Maternal reproductive investment can critically influence offspring phenotype, and thus these maternal effects are expected to be under strong natural selection. Knowledge on the extent of heritable variation in the physiological mechanisms underlying maternal effects is however limited. In birds, resource allocation to eggs is a key mechanism for mothers to affect their offspring and different components of the egg may or may not be independently adjusted. We studied the heritability of egg components and their genetic and phenotypic covariation in great tits (Parus major), using captive-bred full siblings of wild origin. Egg mass, testosterone (T) and androstenedione (A4) hormone concentrations showed moderate heritability, in agreement with earlier findings. Interestingly, yolk triiodothyronine hormone (T3), but not its precursor, thyroxine hormone (T4), concentration was heritable. An immune factor, albumen lysozyme, showed moderate heritability, but yolk immunoglobulins (IgY) did not. The genetic correlation estimates were moderate but statistically nonsignificant; a trend for a positive genetic correlation was found between A4 and egg mass, T and lysozyme and IgY and lysozyme, respectively. Interestingly, phenotypic correlations were found only between A4 and T, and T4 and T3, respectively. Given that these egg components are associated with fitness-related traits in the offspring (and mother), and that we show that some components are heritable, it opens the possibility that natural selection may shape the rate and direction of phenotypic change via egg composition.


Assuntos
Androgênios/genética , Gema de Ovo/química , Fatores Imunológicos/genética , Padrões de Herança , Aves Canoras/genética , Hormônios Tireóideos/genética , Animais , Feminino , Imunoglobulinas/genética , Modelos Genéticos , Muramidase/genética , Fenótipo , Seleção Genética
5.
BMC Palliat Care ; 15: 36, 2016 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-27009550

RESUMO

BACKGROUND: Empirical knowledge around palliative care provision and needs of people with intellectual disabilities is extremely limited, as is the availability of research resources, including expertise and funding. This paper describes a consultation process that sought to develop an agenda for research priorities for palliative care of people with intellectual disabilities in Europe. METHODS: A two-day workshop was convened, attended by 16 academics and clinicians in the field of palliative care and intellectual disability from six European countries. The first day consisted of round-table presentations and discussions about the current state of the art, research challenges and knowledge gaps. The second day was focused on developing consensus research priorities with 12 of the workshop participants using nominal group technique, a structured method which involved generating a list of research priorities and ranking them in order of importance. RESULTS: A total of 40 research priorities were proposed and collapsed into eleven research themes. The four most important research themes were: investigating issues around end of life decision making; mapping the scale and scope of the issue; investigating the quality of palliative care for people with intellectual disabilities, including the challenges in achieving best practice; and developing outcome measures and instruments for palliative care of people with intellectual disabilities. CONCLUSIONS: The proposal of four major priority areas and a range of minor themes for future research in intellectual disability, death, dying and palliative care will help researchers to focus limited resources and research expertise on areas where it is most needed and support the building of collaborations. The next steps are to cross-validate these research priorities with people with intellectual disabilities, carers, clinicians, researchers and other stakeholders across Europe; to validate them with local and national policy makers to determine how they could best be incorporated in policy and programmes; and to translate them into actual research studies by setting up European collaborations for specific studies that require such collaboration, develop research proposals and attract research funding.


Assuntos
Consenso , Deficiência Intelectual/terapia , Cuidados Paliativos/métodos , Pesquisa , Europa (Continente) , Pesquisa sobre Serviços de Saúde , Humanos
6.
J Evol Biol ; 26(12): 2739-45, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24118141

RESUMO

Many organisms advance their seasonal reproduction in response to global warming. In birds, which regress their gonads to a nonfunctional state each winter, these shifts are ultimately constrained by the time required for gonadal development in spring. Gonadal development is photoperiodically controlled and shows limited phenotypic plasticity in relation to environmental factors, such as temperature. Heritable variation in the time required for full gonadal maturation to be completed, based on both onset and speed of development and resulting in seasonally different gonad sizes among individuals, is thus a crucial prerequisite for an adaptive advancement of seasonal reproduction in response to changing temperatures. We measured seasonal gonadal development in climate-controlled aviaries for 144 great tit (Parus major) pairs, which consisted of siblings obtained as whole broods from the wild. We show that the extent of ovarian follicle development (follicle size) in early spring is highly heritable (h(2) = 0.73) in females, but found no heritability of the extent of testis development in males. However, heritability in females decreased as spring advanced, caused by an increase in environmental variance and a decrease in additive genetic variation. This low heritability of the variation in a physiological mechanism underlying reproductive timing at the time of selection may hamper genetic adaptation to climate change, a key insight as this great tit population is currently under directional selection for advanced egg-laying.


Assuntos
Genitália/anatomia & histologia , Estações do Ano , Aves Canoras/anatomia & histologia , Animais , Feminino , Masculino
7.
Z Gerontol Geriatr ; 45(7): 630-6, 2012 Oct.
Artigo em Alemão | MEDLINE | ID: mdl-22948732

RESUMO

In the coming years, a growing number of people with an intellectual disability will reach retirement age. In line with the change of paradigms, the leading ideas of participation, inclusion and self-determination have become the principles of the ideological and conceptual framework in social services for people with disabilities. However, in many places convincing concepts and arrangements of support for elderly people with intellectual disabilities are lacking, particularly beyond institutionalized concepts. The research project "Lebensqualität inklusiv(e)" (quality of life included) tries to bridge this gap. On the base of an estimation of the demographic development for this group of people, models of best practice have been documented and evaluated focusing on living conditions and the special requirements for elderly people with intellectual disabilities in order to gather ideas for the development of arrangements of support. The results show that an interdisciplinary cooperation is indispensable.


Assuntos
Serviços de Saúde para Idosos/organização & administração , Deficiência Intelectual/epidemiologia , Deficiência Intelectual/reabilitação , Modelos Organizacionais , Qualidade de Vida , Idoso , Idoso de 80 Anos ou mais , Feminino , Alemanha/epidemiologia , Humanos , Masculino
8.
Phytomedicine ; 19(8-9): 665-71, 2012 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-22475718

RESUMO

Silexan, a novel lavender oil preparation for oral use, has been authorized in Germany for the treatment of states of restlessness during anxious mood. An open-label, exploratory trial was performed to assess the potential of the medicinal product in the treatment of restlessness caused by anxiety as related to several disorders. Outcome measures included the Symptom Checklist-90-Revised (SCL-90-R), von Zerssen's Depression Scale (D-S), the 36-item Short Form Health Survey Questionnaire (SF-36), and a sleep diary. 50 male and female patients with neurasthenia (ICD-10 F48.0), post-traumatic stress disorder (PSD; F43.1), or somatization disorder (F45.0, F45.1) were included to receive 1 × 80 mg/day Silexan over 6 weeks; 47 could be analyzed for efficacy as full analysis set. At baseline, patients suffered from restlessness (96%), depressed mood (98%), sleep disturbances (92%), or anxiety (72%). Of those, resp. 62%, resp. 57%, resp.51%, resp. 62% showed improvements during treatment (p < 0.001). For all patients, mean D-S score decreased by 32.7% and SCL-90-R Global Severity Index by 36.4% as compared to baseline, (p < 0.001), while the SF-36 Mental Health Score increased by 48.2% (p < 0.001). Waking-up frequency (p = 0.002), Waking-up duration (p < 0.001) and morning tiredness (p = 0.005) were reduced, while efficiency of sleep (p = 0.018) and mood (p = 0.03) improved. Patients suffering from neurasthenia or PSD showed comparable improvements with most outcomes. The results in this trial justify to further investigate Silexan in disorders with accompanying restlessness caused by sub-threshold anxiety. Adverse reactions, predominantly gastrointestinal complaints, were judged as mild or moderate.


Assuntos
Neurastenia/tratamento farmacológico , Óleos Voláteis/uso terapêutico , Óleos de Plantas/uso terapêutico , Transtornos Somatoformes/tratamento farmacológico , Transtornos de Estresse Pós-Traumáticos/tratamento farmacológico , Administração Oral , Adulto , Idoso , Ansiedade/tratamento farmacológico , Depressão/tratamento farmacológico , Feminino , Humanos , Lavandula , Masculino , Pessoa de Meia-Idade , Neurastenia/psicologia , Óleos Voláteis/efeitos adversos , Óleos de Plantas/efeitos adversos , Agitação Psicomotora/tratamento farmacológico , Transtornos do Sono-Vigília/tratamento farmacológico , Transtornos Somatoformes/psicologia , Transtornos de Estresse Pós-Traumáticos/psicologia , Resultado do Tratamento
10.
Curr Biol ; 11(23): 1885-90, 2001 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-11728313

RESUMO

Cells have a recurrent need for the correct assembly of protein-nucleic acid complexes. We have studied a yeast homolog of the smallest subunit of chromatin assembly factor 1 (CAF1), encoded by YMR131c and termed "RRB1". Unlike other yeast homologs, Msi1p, and Hat2p, Rrb1p is essential for cell viability. Impairment of Rrb1p function results in decreased levels of free 60S ribosomal subunits and the appearance of half-mer polysomes, suggesting its involvement in ribosome biogenesis. Using tandem affinity purification (TAP ) combined with mass spectrometry, we show that Rrb1p is associated with ribosomal protein L3. A fraction of Rrb1p is also found in a protein-precursor rRNA complex containing at least ten other early-assembling ribosomal proteins. We propose that Rrb1p is required for proper assembly of preribosomal particles during early ribosome biogenesis, presumably by targeting L3 onto the 35S precursor rRNA. This action may resemble the mechanism by which CAF1 assembles histones H3/H4 onto newly replicated DNA.


Assuntos
Proteínas Cromossômicas não Histona , Proteínas de Ligação a DNA/fisiologia , Ribossomos/metabolismo , Saccharomyces cerevisiae/fisiologia , Sequência de Bases , Fator 1 de Modelagem da Cromatina , Primers do DNA , Espectrometria de Massas , Hibridização de Ácido Nucleico , Precursores de RNA/metabolismo , RNA Ribossômico/isolamento & purificação , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Proteínas Ribossômicas/isolamento & purificação , Proteínas Ribossômicas/metabolismo
11.
Biochimie ; 83(1): 5-12, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11254968

RESUMO

We review the processes leading to the structural modifications required for the initiation of replication in Escherichia coli, the conversion of the initial complex to the open complex, loading of helicase, and the assembly of two replication forks. Rules for the binding of DnaA to its binding sites are derived, and the properties of ATP-DnaA are described. We provide new data on cooperative interaction and dimerization of DnaA proteins of E. coli, Streptomyces and Thermus thermophilus, and on the stoichiometry of DnaA-oriC complexes of E. coli.


Assuntos
Proteínas de Bactérias/metabolismo , Replicação do DNA , DNA Bacteriano/metabolismo , Proteínas de Ligação a DNA/metabolismo , Proteínas de Escherichia coli , Origem de Replicação , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Sequência de Bases , DNA Helicases/genética , DNA Helicases/metabolismo , DNA Bacteriano/genética , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/genética , Dimerização , DnaB Helicases , Escherichia coli/genética , Escherichia coli/metabolismo , Modelos Moleculares , Dados de Sequência Molecular , Sequências Reguladoras de Ácido Nucleico/genética , Streptomyces/genética , Streptomyces/metabolismo , Thermus thermophilus/genética , Thermus thermophilus/metabolismo
12.
J Mol Biol ; 299(3): 655-65, 2000 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-10835275

RESUMO

The chromosomal replication origin oriC and the gene encoding the replication initiator protein DnaA from Thermus thermophilus have been identified and cloned into an Escherichia coli vector system. The replication origin is composed of 13 characteristically arranged DnaA boxes, binding sites for the DnaA protein, and an AT-rich stretch, followed by the dnaN gene. The dnaA gene is located upstream of the origin and expresses a typical DnaA protein that follows the division into four domains, as with other members of the DnaA protein family. Here, we report the purification of Thermus-DnaA (Tth-DnaA) and characterize the interaction of the purified protein with the replication origin, with regard to the binding kinetics and stoichiometry of this interaction. Using gel retardation assays, surface plasmon resonance (SPR) and electron microscopy, we show that, unlike the E. coli DnaA, Tth-DnaA does not recognize a single DnaA box, instead a cluster of three tandemly repeated DnaA boxes is the minimal requirement for specific binding. The highest binding affinities are observed with full-length oriC or six clustered, tandemly repeated DnaA boxes. Furthermore, high-affinity DNA-binding of Tth-DnaA is dependent on the presence of ATP. The Thermus DnaA/oriC interaction will be compared with oriC complex formation generated by other DnaA proteins.


Assuntos
Proteínas de Bactérias/metabolismo , Cromossomos Bacterianos/metabolismo , Proteínas de Ligação a DNA/metabolismo , Origem de Replicação/genética , Thermus thermophilus/enzimologia , Thermus thermophilus/genética , Difosfato de Adenosina/metabolismo , Adenosina Trifosfatases/genética , Adenosina Trifosfatases/isolamento & purificação , Adenosina Trifosfatases/metabolismo , Adenosina Trifosfatases/ultraestrutura , Trifosfato de Adenosina/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/isolamento & purificação , Proteínas de Bactérias/ultraestrutura , Sequência de Bases , Sítios de Ligação , Cromossomos Bacterianos/genética , Cromossomos Bacterianos/ultraestrutura , Clonagem Molecular , DNA Bacteriano/genética , DNA Bacteriano/metabolismo , DNA Bacteriano/ultraestrutura , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/isolamento & purificação , Proteínas de Ligação a DNA/ultraestrutura , Genes Bacterianos/genética , Hidrólise , Cinética , Microscopia Eletrônica , Dados de Sequência Molecular , Ligação Proteica , Estrutura Terciária de Proteína , Ressonância de Plasmônio de Superfície , Sequências de Repetição em Tandem/genética , Termodinâmica
13.
J Am Mosq Control Assoc ; 15(4): 510-9, 1999 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-10612615

RESUMO

This study attempted to find organisms for the biological control of the mosquito Aedes aegypti in Costa Rica. Copepods of the genera Arctodiaptomus, Eucylops, Mesocyclops, Megacyclops, and Thermocyclops were collected in several parts of the country and cultured for laboratory evaluations. Mesocyclops thermocyclopoides was the most successful species in reducing the number of larval Ae. aegypti (7.3 larvae in 24 h at a density of 200 Aedes/liter). Arctodiaptomus dorsalis, Eucyclops cf. bondi, Eucyclops leptacanthus, Megacyclops sp., and Thermocyclops decipens were not effective predators. In cage simulation trials, M. thermocyclopoides showed 100% larval reduction after 4 wk and adult mosquitoes disappeared after 7 wk. The copepod was able to survive in Aechmea sp. bromeliads under laboratory conditions. In field trials under 3 different climatic conditions M. thermocyclopoides survived 2-5 months in bromeliad leaf axils and 3-6 months in used car tires. In tires, this species reduced the number of larval Ae. aegypti 79, 90, and 99% in tropical dry, moderate, and humid climates, respectively. An El Niño phenomenon affected the results by drought, which apparently also caused a decline in the population of the predatory mosquito Toxorhynchites haemorrhoidalis superbus. Considering these severe test conditions, M. thermocyclopoides might be a promising predator for mosquito control in Costa Rica.


Assuntos
Aedes , Crustáceos , Controle de Mosquitos/métodos , Animais , Clima , Costa Rica , Dieta , Larva , Dinâmica Populacional
14.
Biochimie ; 81(8-9): 819-25, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-10572294

RESUMO

Functional domains of the initiator protein DnaA of Escherichia coli have been defined. Domain 1, amino acids 1-86, is involved in oligomerization and in interaction with DnaB. Domain 2, aa 87-134, constitutes a flexible loop. Domain 3, aa 135-373, contains the binding site for ATP or ADP, the ATPase function, a second interaction site with DnaB, and is required for local DNA unwinding. Domain 4 is required and sufficient for specific binding to DNA. We show that there are three different types of cooperative interactions during the DNA binding of DnaA proteins from E. coli, Streptomyces lividans, and Thermus thermophilus: i) binding to distant binding sites; ii) binding to closely spaced binding sites; and iii) binding to non-canonical binding sites.


Assuntos
Proteínas de Bactérias/química , Proteínas de Ligação a DNA/química , Sequência de Aminoácidos , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Sequência de Bases , Sítios de Ligação/genética , DNA Bacteriano/genética , DNA Bacteriano/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Cinética , Dados de Sequência Molecular , Estrutura Terciária de Proteína/genética
15.
Acta Crystallogr D Biol Crystallogr ; 54(Pt 5): 1008-11, 1998 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-9757122

RESUMO

Portal proteins are cyclical oligomers which play essential roles in bacteriophage pro-capsid formation, DNA packaging, and in connector formation. Bacteriophage SPP1 portal protein (gp6) is a turbine-like molecule with 13-fold symmetry [Dube et al. (1993) EMBO J. 12, 1303-1309]. The purified protein was crystallized with polyethylene glycol 400 as the precipitating agent using the vapor-diffusion method. Salt conditions were selected based on the properties of gp6 in different ionic environments. X-ray diffraction data up to a resolution of 7.85 A were measured from frozen crystals with orthorhombic space group C2221 and cell dimensions a = 180.5 (5), b = 223.5 (5), c = 417 (1) A. The asymmetric unit contains one tridecameric portal protein with 57.3 kDa subunits. The self-rotation searches confirm the 13-fold symmetry of the crystallized protein.


Assuntos
Capsídeo/química , Colífagos/química , Conformação Proteica , Proteínas Virais/química , Cristalização , Cristalografia por Raios X , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/isolamento & purificação , Proteínas Virais/isolamento & purificação
16.
Proteins ; 28(1): 1-9, 1997 May.
Artigo em Inglês | MEDLINE | ID: mdl-9144786

RESUMO

The secondary structure of DnaA protein and its interaction with DNA and ribonucleotides has been predicted using biochemical, biophysical techniques, and prediction methods based on multiple-sequence alignment and neural networks. The core of all proteins from the DnaA family consists of an "open twisted alpha/beta structure," containing five alpha-helices alternating with five beta-strands. In our proposed structural model the interior of the core is formed by a parallel beta-sheet, whereas the alpha-helices are arranged on the surface of the core. The ATP-binding motif is located within the core, in a loop region following the first beta-strand. The N-terminal domain (80 aa) is composed of two alpha-helices, the first of which contains a potential leucine zipper motif for mediating protein-protein interaction, followed by a beta-strand and an additional alpha-helix. The N-terminal domain and the alpha/beta core region of DnaA are connected by a variable loop (45-70 aa); major parts of the loop region can be deleted without loss of protein activity. The C-terminal DNA-binding domain (94 aa) is mostly alpha-helical and contains a potential helix-loop-helix motif. DnaA protein does not dimerize in solution; instead, the two longest C-terminal alpha-helices could interact with each other, forming an internal "coiled coil" and exposing highly basic residues of a small loop region on the surface, probably responsible for DNA backbone contacts.


Assuntos
Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Replicação do DNA , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/genética , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Sequência de Aminoácidos , Proteínas de Bactérias/metabolismo , Cromatografia em Gel , Dicroísmo Circular , Proteínas de Ligação a DNA/metabolismo , Teste de Complementação Genética , Modelos Químicos , Modelos Teóricos , Dados de Sequência Molecular , Relação Estrutura-Atividade
17.
J Biol Chem ; 270(29): 17622-6, 1995 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-7615570

RESUMO

Equilibrium and kinetic rate constants were determined for the binding of the initiator protein DnaA of Escherichia coli to its binding site, the non-palindromic 9-bp DnaA box, using gel retardation techniques. The dissociation constant for specific binding was between 1 and 50 nM for individual DnaA boxes on 21-bp double-stranded oligonucleotides. Only DnaA boxes of the sequence TT(A/T)TNCACA resulted in specific fragment retention. Both the 9-bp consensus sequence and flanking sequences determined the binding efficiency. One DnaA monomer was found to bind to a DnaA box and to induce a bend of about 40 degrees.


Assuntos
Proteínas de Bactérias/metabolismo , Replicação do DNA , Proteínas de Ligação a DNA/metabolismo , DNA/metabolismo , Escherichia coli/genética , Sequência de Bases , Sítios de Ligação , Cinética , Dados de Sequência Molecular
18.
Chromosoma ; 102(1 Suppl): S1-6, 1992.
Artigo em Inglês | MEDLINE | ID: mdl-1291230

RESUMO

We probed the complex between oriC and DnaA protein using two types of mutants in oriC. Base changes in the DnaA binding sites, DnaA boxes, had little effect on origin function. Mutations which change the distance between DnaA boxes R3 and R4, on the other hand, inactivated oriC unless the mutation deleted or inserted one complete helical turn. Origins with other 10 base pair insertions in the interval between DnaA boxes R2 and R3 were functional, but not insertions in the R1-R2 interval. FIS protein binds to a bipartite site in oriC between DnaA boxes R2 and R3. A model for the oriC/DnaA complex based on these results suggests an array of DnaA monomers with a 34 A spacing upon which oriC is arranged.


Assuntos
Proteínas de Bactérias/metabolismo , Proteínas de Transporte/metabolismo , Replicação do DNA/genética , Proteínas de Ligação a DNA/metabolismo , Proteínas de Escherichia coli , Escherichia coli/genética , Sequência de Bases , Sítios de Ligação , DNA Bacteriano/metabolismo , Fator Proteico para Inversão de Estimulação , Fatores Hospedeiros de Integração , Modelos Genéticos , Dados de Sequência Molecular , Mutação , Ligação Proteica
19.
Biomed Biochim Acta ; 48(1): 23-32, 1989.
Artigo em Inglês | MEDLINE | ID: mdl-2775249

RESUMO

Cathepsin E (EC 3.4.23.--) has been isolated from rat spleen. The procedure included autolysis at pH 4.2 which was probably the reason why we isolated a polypeptide of Mr 42 kDa instead of 90 kDa. The latter is reported in the literature to be the Mr of native cathepsin E. The enzyme dissociates under reducing conditions in two identical monomers. In our preparation a mechanism different from reduction must be active producing the 42 kDa polypeptide. This enzyme was hard to distinguish from cathepsin D (EC 3.4.23.5.) which shows similar properties such as size, substrate specificity, stability in 6 M urea, and dependence of the activity on pH. The clear distinction between the two enzymes was proven on the basis of immunochemical reactions. Antibodies to both cathepsins, D and E, did not show any crossreaction with the nonrelated antigen.


Assuntos
Catepsinas/isolamento & purificação , Baço/enzimologia , Animais , Western Blotting , Catepsina D/metabolismo , Catepsina E , Catepsinas/metabolismo , Cromatografia por Troca Iônica , Eletroforese em Gel de Poliacrilamida , Estabilidade Enzimática , Cinética , Peso Molecular , Ratos , Especificidade por Substrato
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