RESUMEN
OBJECTIVE: To describe the challenges of service coordination through the National Disaster Medical System (NDMS) for Hurricane Maria evacuees, particularly those on dialysis. DESIGN: Public health report. SETTING: Georgia. REPORT: On November 25, 2017, there were 208 patients evacuated to Georgia in response to Hurricane Maria receiving NDMS support. Most were evacuated from the US Virgin Islands (97 percent) and the remaining from Puerto Rico (3 percent); 73 percent of these patients were on dialysis, all from the US Virgin Islands. From the beginning of the evacuation response through November 25, 2017, there were 282 patients evacuated to Georgia via NDMS, with a median length of coverage through NDMS for those on and not on dialysis of 60 and 16 days, respectively. CONCLUSION: The limited capacity and capability of dialysis centers currently in the US Virgin Islands are delaying the return to home of many Hurricane Maria evacuees who are on dialysis.
Asunto(s)
Tormentas Ciclónicas , Planificación en Desastres/organización & administración , Salud Pública , Conducta Cooperativa , Georgia , HumanosRESUMEN
The catalytic domains of class I aminoacyl-tRNA synthetases are built around a conserved Rossmann nucleotide binding fold, with additional polypeptide domains responsible for tRNA binding or hydrolytic editing of misacylated substrates. Structural comparisons identified a conserved motif bridging the catalytic and anticodon binding domains of class Ia and Ib enzymes. This stem contact fold (SCF) has been proposed to globally orient each enzyme's cognate tRNA by interacting with the inner corner of the L-shaped tRNA. Despite the structural similarity of the SCF among class Ia/Ib enzymes, the sequence conservation is low. We replaced amino acids of the MetRS SCF with portions of the structurally similar glutaminyl-tRNA synthetase (GlnRS) motif or with alanine residues. Chimeric variants retained significant tRNA methionylation activity, indicating that structural integrity of the helix-turn-strand-helix motif contributes more to tRNA aminoacylation than does amino acid identity. In contrast, chimeras were significantly reduced in methionyl adenylate synthesis, suggesting a role for the SCF in formation of a structured active site domain. A highly conserved aspartic acid within the MetRS SCF is proposed to make an electrostatic interaction with an active site lysine; these residues were replaced with alanines or conservative substitutions. Both methionyl adenylate formation and methionine transfer were impaired, and activity was not significantly recovered by making the compensatory double substitution.
Asunto(s)
Dominio Catalítico , Proteínas de Escherichia coli/química , Escherichia coli/enzimología , Metionina-ARNt Ligasa/química , Secuencias de Aminoácidos , Secuencia de Aminoácidos , Secuencia Conservada , Escherichia coli/química , Escherichia coli/genética , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Cinética , Metionina-ARNt Ligasa/genética , Metionina-ARNt Ligasa/metabolismo , Datos de Secuencia Molecular , Mutación , Pliegue de Proteína , Estructura Secundaria de Proteína , Alineación de SecuenciaRESUMEN
The assignment of AUG codons to methionine remains a central question of the evolution of the genetic code. We have unveiled a strategy for the discrimination among tRNAs containing CAU (AUG-decoding) anticodons. Mycoplasma penetrans methionyl-tRNA synthetase can directly differentiate between tRNA(Ile)(CAU) and tRNA(Met)(CAU) transcripts (a recognition normally achieved through the modification of anticodon bases). This discrimination mechanism is based only on interactions with the acceptor stems of tRNA(Ile)(CAU) and tRNA(Met)(CAU). Thus, in certain species, the fidelity of translation of methionine codons requires a discrimination mechanism that is independent of the information contained in the anticodon.