RESUMO
We use a new gel electrophoretic analysis to map the thermodynamically defined DNA binding domain of Escherichia coli CAP protein in the lac promoter. Strong binding interactions span a 28-30 bp duplex DNA region, substantially larger than that found for typical repressors. Sequence changes outside the central 28 bp of the binding site are found to affect the electrophoretically observed extent of bending. We also report a study of the DNA bending induced at a symmetrized CAP binding site, compared with the wild-type site; binding and bending are stronger at the upstream than at the downstream half of the wild-type site. Bends of the estimated 90 degrees - 180 degrees magnitude could play a vital regulatory role by producing tertiary structure in a local DNA domain, and by storing elastic energy for subsequent use in transcription or replication.
Assuntos
Proteínas de Bactérias/metabolismo , DNA Bacteriano/metabolismo , Escherichia coli/metabolismo , Sequência de Bases , Sítios de Ligação , Escherichia coli/genética , Conformação de Ácido Nucleico , Regiões Promotoras GenéticasAssuntos
Raiva/diagnóstico , Animais , Anticorpos Antivirais/análise , Apneia/etiologia , Autopsia , Sangue , Encéfalo/patologia , Dióxido de Carbono/sangue , Criança , Clorpromazina/uso terapêutico , Diabetes Insípido/etiologia , Imunofluorescência , Parada Cardíaca/etiologia , Humanos , Concentração de Íons de Hidrogênio , Hipercinese/tratamento farmacológico , Hipercinese/etiologia , Hipotensão/etiologia , Masculino , Camundongos , Oxigênio/sangue , Raiva/sangue , Raiva/complicações , Raiva/tratamento farmacológico , Raiva/imunologia , Raiva/patologia , Raiva/terapia , Vírus da Raiva/isolamento & purificação , Convulsões/tratamento farmacológico , Convulsões/etiologia , Vasopressinas/metabolismoRESUMO
The use of indirect methods for the determination by atomic-absorption spectrometry of those elements not normally amenable to sensitive determination by this technique is reviewed. The available indirect methods are classified into five general types of procedure; specific reported procedures for the determination of metals, non-metals and some compounds are discussed.