RESUMO
The BARD1 N-terminal RING domain binds BRCA1 while the BARD1 C-terminal ankyrin and tandem BRCT repeat domains bind CstF-50 to modulate mRNA processing and RNAP II stability in response to DNA damage. Here we characterize the BARD1 structural biochemistry responsible for CstF-50 binding. The crystal structure of the BARD1 BRCT domain uncovers a degenerate phosphopeptide binding pocket lacking the key arginine required for phosphopeptide interactions in other BRCT proteins. Small angle X-ray scattering together with limited proteolysis results indicates that ankyrin and BRCT domains are linked by a flexible tether and do not adopt a fixed orientation relative to one another. Protein pull-down experiments utilizing a series of purified BARD1 deletion mutants indicate that interactions between the CstF-50 WD-40 domain and BARD1 involve the ankyrin-BRCT linker but do not require ankyrin or BRCT domains. The structural plasticity imparted by the ANK-BRCT linker helps to explain the regulated assembly of different protein BARD1 complexes with distinct functions in DNA damage signaling including BARD1-dependent induction of apoptosis plus p53 stabilization and interactions. BARD1 architecture and plasticity imparted by the ANK-BRCT linker are suitable to allow the BARD1 C-terminus to act as a hub with multiple binding sites to integrate diverse DNA damage signals directly to RNA polymerase.
Assuntos
Fator Estimulador de Clivagem/química , Fator Estimulador de Clivagem/metabolismo , Proteínas Supressoras de Tumor/química , Proteínas Supressoras de Tumor/metabolismo , Ubiquitina-Proteína Ligases/química , Ubiquitina-Proteína Ligases/metabolismo , Sítios de Ligação , Fator Estimulador de Clivagem/genética , Cristalografia por Raios X , Dano ao DNA , Humanos , Técnicas In Vitro , Modelos Moleculares , Poliadenilação , Domínios e Motivos de Interação entre Proteínas , Estrutura Terciária de Proteína , Processamento Pós-Transcricional do RNA , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Espalhamento a Baixo Ângulo , Proteínas Supressoras de Tumor/genética , Ubiquitina-Proteína Ligases/genética , Difração de Raios XRESUMO
BACKGROUND: Infusion therapy through intravenous (IV) access is a therapeutic option used in the treatment of many hospitalized patients. IV therapy is complex, potentially dangerous and error prone. The objectives were to ascertain the drug-related problems (DRPs) involved in IV medication administration and further to develop strategies to reduce and prevent the occurrence of DRPs during IV administration. MATERIALS AND METHODS: A prospective observational study was carried out for a period of 4 months. Patients receiving more than two medications through IV route were included and studied. RESULTS: Of 110 patients, 76 (69.09%) were male and the rest were female. Nearly, half of the patients (46.3%, n = 51) were reported with DRPs. Of the 80 DRPs (72.72%) documented, 61 problems (55.4%) were seen in patients given IV medications through peripheral line. Among the DRPs majority seen were incompatibilities (40.9%, n = 45), followed by complications developed (12.7%, n = 14), errors in rate of administration (10.9%), and dilution errors (8%). To study the association of DRPs among gender, statistical analysis was performed and significant association was seen between DRPs and gender (P = 0.03). CONCLUSION: Among the reported DRPs, simultaneous IV administration of two incompatible drugs was the main predicament faced.