| Abstract
| - Template Activating Factor (TAF) I remodels the adenovirus (Ad) core structure composedof the Ad genome DNA and basic viral core proteins and stimulates in vitro DNA replication andtranscription of the Ad core. We have recently reported that TAF-I binds to major core protein VII andforms DNA−protein VII−TAF-I ternary complexes in vitro and in vivo. Further to understand themechanism of remodeling of the Ad core, we characterized the interaction mode between the precursorof protein VII (pre-VII) and either DNA or TAF-I by means of biochemical and biophysicochemicalmethods. We found that a major binding region of pre-VII with both DNA and the acidic carboxyl-terminal region of TAF-I lies in the arginine-rich region of pre-VII. Both amino-terminal and carboxyl-terminal regions of pre-VII without the arginine-rich region directly bound to DNA and supported theDNA binding activity of the arginine-rich region. A TAF-I mutant protein lacking the acidic carboxyl-terminal region bound preferentially to the carboxyl-terminal region of pre-VII containing the arginine-rich region rather than the amino-terminal region of pre-VII. Thus, DNA interacted with the entire regionof pre-VII, while TAF-I bound preferentially to the carboxyl-terminal region of pre-VII. This bindingmode suggests the formation of the ternary complexes among DNA, protein VII, and TAF-I. On the basisof the binding modes in binary systems, we discussed the remodeling mechanism of the Ad core in earlyphases of infection.
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