Copyright information:Taken from "Complex interactions of HIV-1 nucleocapsid protein with oligonucleotides"Nucleic Acids Research 2006;34(2):472-484.Published online 24 Jan 2006PMCID:PMC1351370.© The Author 2006. Published by Oxford University Press. All rights reserved (TG) was titrated into a 400 nM solution of NC and tryptophan fluorescence was monitored as described in Materials and Methods. The fluorescence readings were divided by the fluorescence of NC before addition of (TG) to obtain the normalized fluorescence shown here. Attempts were made to fit the data assuming a 1:1 binding system (dashed line) (giving a of 3.4 ± 0.07 nM) or the more complex model shown in (solid grey line). The results shown here are normalized by dividing by the fluorescence value of NC alone. As indicated in Supplementary equation 5, the final fluorescence obtained after several equivalents of (TG) had been added [i.e. the residual fluorescence of NC bound to (TG)] was subtracted from these values before attempting to fit the curves.