RESUMO
Protein-chromophore interactions are a central component of a wide variety of critical biological processes such as color vision and photosynthesis. To understand the fundamental elements that contribute to spectral tuning of a chromophore inside the protein cavity, we redesigned human cellular retinol binding protein II (hCRBPII) to fully encapsulate all-trans-retinal and form a covalent bond as a protonated Schiff base. This system, using rational mutagenesis designed to alter the electrostatic environment within the binding pocket of the host protein, enabled regulation of the absorption maximum of the pigment in the range of 425 to 644 nanometers. With only nine point mutations, the hCRBPII mutants induced a systematic shift in the absorption profile of all-trans-retinal of more than 200 nanometers across the visible spectrum.
Assuntos
Retinaldeído/análogos & derivados , Proteínas Celulares de Ligação ao Retinol/química , Absorção , Elétrons , Humanos , Mutagênese , Mutação Puntual , Retinaldeído/química , Proteínas Celulares de Ligação ao Retinol/genética , Eletricidade EstáticaRESUMO
The proportion of children suffering from chronic illnesses--such as asthma and obesity, which have significant environmental components--is increasing. Chronic disease states previously seen only in adulthood are emerging during childhood, and health inequalities by social class are increasing. Advocacy to ensure environmental health and to protect from the biological embedding of toxic stress has become a fundamental part of pediatrics. We have presented the rationale for addressing environmental and social determinants of children's health, the epidemiology of issues facing children's health, recent innovations in pediatric medical education that have incorporated public health principles, and policy opportunities that have arisen with the passage of the 2010 Patient Protection and Affordable Care Act.
Assuntos
Necessidades e Demandas de Serviços de Saúde , Pediatria/organização & administração , Atenção Primária à Saúde/organização & administração , Administração em Saúde Pública , Adolescente , Asma/epidemiologia , Criança , Exposição Ambiental/estatística & dados numéricos , Saúde Ambiental , Feminino , Necessidades e Demandas de Serviços de Saúde/organização & administração , Necessidades e Demandas de Serviços de Saúde/normas , Humanos , Seguro Saúde , Masculino , Saúde Mental , Obesidade/epidemiologia , Saúde Bucal , Pediatria/educação , Pediatria/normas , Pobreza , Atenção Primária à Saúde/normas , Administração em Saúde Pública/educação , Administração em Saúde Pública/normas , Estados Unidos/epidemiologia , Violência/estatística & dados numéricosRESUMO
Cellular Retinoic Acid Binding Protein II (CRABPII) has been reengineered to specifically bind and react with all-trans-retinal to form a protonated Schiff base. Each step of this process has been dissected and four residues (Lys132, Tyr134, Arg111, and Glu121) within the CRABPII binding site have been identified as crucial for imine formation and/or protonation. The precise role of each residue has been examined through site directed mutagenesis and crystallographic studies. The crystal structure of the R132K:L121E-CRABPII (PDB-3I17) double mutant suggests a direct interaction between engineered Glu121 and the native Arg111, which is critical for both Schiff base formation and protonation.
