SACRAMENTO - The federal corruption probe of state Sen. Don Perata bubbles with the tension of a television drama. The central character is a savvy 59-year-old East Bay Democrat with a penchant for double-breasted suits who relishes comparisons to a Mafia boss. A former high school civics teacher and the son of an Italian-American dairyman, Perata rose through the byzantine world of Oakland politics to become leader of the state Senate. But now a federal investigation into his dealings with relatives and close associates threatens to undermine everything Perata has worked for. The case has the makings of a ``Law...