Characterization of the hantaan nucleocapsid protein-ribonucleic acid interaction

The nucleocapsid (N) protein functions in hantavirus replication through it s interactions with the viral genomic and antigenomic RNAs. To address the biological functions of the N protein, it was critical to first define this binding interaction. The dissociation constant, K-d, for the interaction o f the Hantaan virus (HTNV) N protein and its genomic S segment (vRNA) was m easured under several solution conditions. Overall, increasing the NaCl and Mg2+ in these binding reactions had little impact on the K-d. However, the HTNV N protein showed an enhanced specificity for HTNV vRNA as compared wi th the S segment open reading frame RNA or a nonviral RNA with increasing i onic strength and the presence of Mg2+. In contrast, the assembly of Sin No mbre virus N protein-HTNV vRNA complexes was inhibited by the presence of M g2+ Or,increase in the ionic strength. The K-d values for HTNV and Sin Nomb re virus N proteins were nearly identical for the S segment open reading fr ame RNA, showing weak affinity over several binding reaction conditions. Ou r data suggest a model in which specific recognition of the HTNV vRNA by th e HTNV N protein resides in the noncoding regions of the HTNV vRNA.