Molecular Coevolution of Nuclear and Nucleolar Localization Signals inside the Basic Domain of HIV-1 Tat

Abstract

Here, we investigated the molecular mechanism of nuclear localization signal (NLS) and nucleolar localization signal (NoLS) integration into the basic domain of HIV-1 Tat ( 49 RKKRRQRRR 57 ) and found that these two supplementary functions (i.e., function of NLS and NoLS) are embedded in the basic domain amino acid sequence. The integration of NLSs and NoLSs into functional domains of viral proteins enriched with positively charged amino acids is a mechanism that allows the concentration of different functions within small protein regions.