The enhancement of DNA binding ability of a mutated E2 (A338V) protein of HPV-2 / 病毒学报

ABSTRACT

HPV-2 is a very common type of HPV which causes common warts. The E2 protein of virus can repress the activity of the viral early promoter through binding to the specific binding sites in viral LCR. Previously we reported that the repression of a mutated E2 protein of HPV-2 isolated from a patient with huge common wart on the viral early promoter was obviously decreased, and A338V mutation located at the C terminal DNA binding region of E2 protein. In this study, we expressed and purified the recombinant mutated and prototype E2 fusion proteins, both in the contexts of the C terminal and the full length, by prokaryotic expression system. The electrophoretic mobility shift assay showed E2 protein could bind to double-stranded DNA oligos labeled with biotin that covered two E2 binding sites. The DNA binding abilities of both C terminal and full-length mutated E2 proteins were stronger than the prototype analogs. This result indicates that the enhancement of the mutated E2 DNA binding ability may be the molecular mechanism for its impact on the activity of viral promoter, which correlates with the phenotype of extensive common wart.