tokens: A cluster of basic amino acids , KKKR , generated by joining of the sequences encoded by the constitutive exon 13 and the alternative exon 16 , is necessary for the nuclear targeting of 4.1 H , as demonstrated by site directed mutagenesis analysis .
folded_tokens: a cluster of basic amino acid , kkkr , generate by join of the sequence encode by the constitutive exon 13 and the alternative exon 16 , be necessary for the nuclear targeting of 4.1 h , as demonstrate by site directed mutagenesis analysis .