The open reading frame 2 product of cacao swollen shoot badnavirus is a nucleic acid-binding protein

The function of the open reading frame 2 product (p2) of cacao swollen shoot virus (CSSV) and of other badnaviruses is not yet determined. Their carboxyl-termini are lysine and proline rich and also contain alanine residues, amino acids present at the C-termini of histone-like proteins. Full-length CSSV p2 (132 amino acids) or versions truncated at the C-terminus (128, 113, 103, or 101 amino acids) were expressed in Escherichia coli and partially purified. When assayed in nucleic acid-binding tests, p2 was able to interact with CSSV and other double-stranded DNAs and with CSSV and other single-stranded RNA transcripts in a sequence-nonspecific manner. Moreover, this binding activity was progressively lost as the C-terminus was gradually deleted. (C) 1996 Academic Press, Inc.