AUGUSTA – After intense negotiations that stretched through one day and into the next, legislative leaders and Gov. Angus King reached a deal early Saturday that is designed to offset a revenue shortfall of nearly $160 million while largely conforming the state tax structure with federal changes.

The tax-and-spending package also preserves most social service programs that originally were targeted by King for cutbacks when revenue projections were even more pessimistic earlier this year.

In agreeing on the plan, King and the House and Senate leaders left $25 million set aside for the computers-for-students initiative the governor has championed.

The plan also would maintain $15 million in the state Rainy Day Fund, which currently holds about $100 million. The remaining money, however, could go toward offsetting revenue losses resulting from tax conformity.

At the same time, a variety of provisions adjusting state support for public education would boost aid to local schools from $702 million to $731 million, King aide Sue Bell said.

Senate Chairwoman Jill Goldthwait of the Legislature’s Appropriations Committee said the emergency reserve would be available as a “backstop” to ensure that the state could offer tax relief matching that provided by the federal government.

“All of leadership was in the room and said, ‘I do’,” Goldthwait, an independent from Bar Harbor, recounted after Appropriations Committee members joined with King and the Legislature’s top officials to sign off on the deal.

The committee is expected to convene Monday afternoon to vote formally on the package and forward it to the full Legislature.

“I’m fully prepared on Monday for people being queasy about this,” Goldthwait said. “Everybody’s kind of anxious about parts and pieces of it.”

Top King aide Kay Rand said the agreement included concessions on all sides.

“They all had to compromise to get to that place,” she said.

What began as exploratory talks between Democratic and Republican leaders late Friday morning grew into a tedious series of large conferences and smaller huddles – virtually all in private and most behind closed doors – that went on for close to 15 hours.

King returned to the State House late Friday night to meet personally with lawmakers individually and in groups. The final session involving all the players extended through the midnight hour and a unanimous Appropriations Committee declaration of support came after 2 a.m.

King originally had proposed virtually draining the Rainy Day Fund by transferring $98 million to the General Fund to help cover a revenue shortfall once pegged at nearly $250 million.

He subsequently scaled back the proposed level of transfer to about $65 million.

The accord reached Saturday would commit about $10 million more to school aid than the administration had recommended, according to gubernatorial aides.

It also would use about $10 million less than the governor had proposed to take from the Fund for a Healthy Maine, which collects money from Maine’s share of the national tobacco settlement, legislative analysts said.

Success in reaching a deal surprised negotiators on all sides, who at various times during the marathon discussions predicted the talks would break off without agreement.

“Better than the alternative,” Republican Senate President Richard Bennett of Norway said Saturday morning as he headed off from the State House.