ASKA collection AspRS CUG-Ser DNA delivery Escherichia coli GluRS-like M. jannaschii orthogonal pair Metschnikowia RNA metabolism alanyl-tRNA synthetase alternative amino acid and nucleotide repertoires alternative core cellular chemistries amber stop codon suppression anticodon biocontainment biopharmaceuticals branched-chain amino acids class II aminoacyl-tRNA synthetase codon bias cyclic peptides expanded genetic code fluorescence-based screen fluorescent reporter functional conservation gene ontology gene overexpression genetic code expansion genetic firewall genetic isolation genetic tools