Adelson and his wife Miriam donated the combined millions in February to the Congressional Leadership Fund, a super PAC backed by House Speaker John Boehner and other GOP leaders, according to a campaign finance report filed Sunday night.

The GOP super PAC ended the month with $5.1 million in the bank, positioning the group to be a serious player in targeted House races across the country — thanks to the Adelsons.

The Adelsons and their family members helped keep Gingrich’s campaign alive by pouring more than $16 million into Winning Our Future, the super PAC that ran ads to support the former speaker.

The wealthy couple’s shift to supporting the GOP establishment is a promising sign for party operatives, who are hoping to corral some of the deep-pocketed donors that have spent millions on warring super PACs so far this election cycle. It’s also a positive signal for presumptive GOP presidential nominee Mitt Romney, whose campaign is counting on Adelson and other wealthy GOP donors to get behind him as he goes up against President Barack Obama’s hefty war chest.

The Congressional Leadership Fund’s first quarter haul is a major bump from the meager $131,000 it took in between its mid-October launch and the end of last year. Among its other donations this year: $10,000 from Boehner’s leadership PAC the Freedom Project, $25,000 from the Hilmar Cheese Company and $5,000 from the Koch Industries PAC.

Another major GOP super PAC, backed by House Majority Leader Eric Cantor and run by his former aides, didn’t fare nearly as well in the first quarter.

YG Action Fund pulled in just $55,000 in the first three months of this year. The total was barely enough to cover the $52,000 the super PAC spent in March to run radio ads supporting freshman Republican Rep. Adam Kinzinger, who defeated incumbent GOP Rep. Don Manzullo in a heated Illinois primary last month.