Interaction of hepatitis A virus (HAV) precursor proteins 3AB and 3ABC with the 5′ and 3′ termini of the HAV RNA

RNA secondary structures within the terminal nontranslated regions of entero- and rhinoviral genomes interact specifically with viral nonstructural proteins and are required in cis for viral RNA replication. Here we show that recombinant hepatitis A virus (HAV) polypeptide 3ABC specifically interacts in vitro with secondary RNA structures formed at both the 5′ and 3′ terminus of the viral genome. Similar to protein 3AB, HAV 3ABC bound to the 3′ terminal RNA structure which did not interact with the mature proteinase 3C. In contrast to 3AB, 3ABC interacted with RNA stem-loop IIa and combinations of individual secondary structure elements of the 5′ noncoding region. RNA binding of the precursor polypeptide 3ABC was 50 times stronger than that of 3AB and 3C, implicating a specific role of this stable processing intermediate in viral genome replication.