The full-length and N-terminal deletion of ORF2 protein of hepatitis E virus can dimerize

Hepatitis E virus is a human RNA virus containing three open reading frames . Of these ORF2 encodes, the major capsid protein (pORF2), may possess regu latory functions, in addition to a structural one. In this study, we have s hown using the yeast two-hybrid system and in vitro immobilization experime nts that full-length pORF2 is capable of self-association, thus forming a h omodimer. Using mutational analysis we have studied dimerization of various truncated versions of the ORF2 capsid protein using the yeast two-hybrid s ystem and supported our findings with in vitro immobilization experiments. Deletions of pORF2 reveal a loss of the dimerization potential for all dele tions except an N-terminal 127-amino-acid deletion. Our studies suggest tha t the dimerization property of pORF2 may not be amino-acid sequence-depende nt but instead a complex formation of a specific tertiary structure that im parts pORF2 its property to self-associate. (C) 2001 Academic Press.