TORONTO (Reuters) - The Toronto Stock Exchange's main index ended lower as profit-taking in resource shares offset news that Empire Company has bid to take grocery chain Sobeys private in a deal worth about C$1.06 billion.The S&P/TSX composite index closed down 75.33 points, or 0.6 percent, at 13,597.52.

Seven of the TSX index's 10 main groups were lower, led by a 1.1 percent slide in both the energy and materials groups, which together comprise about 40 percent of the market's weight.

"It seems as though we're seeing an element of profit-taking here, particularly with respect to a lot of the commodity names," said Neil Andrew, associate portfolio manager at Leeward Hedge Funds.

"For the most part, we've seen tremendous moves to the upside." he said.

"Every now and then we need to go through that period of digesting some gains."

Energy shares retreated as US crude fell 78 cents to $65.06 a barrel as Middle East tensions eased on news that Iran and the European Union were closer to an agreement on Tehran's nuclear program.

Nexen fell C$2, or 2.9 percent, to C$66.50. The company said it swung to a first-quarter profit, largely due to a production ramp-up at its Buzzard field in the North Sea. Suncor Energy shed C$1.26, or 1.4 percent, to C$90.19 after it said its first-quarter profit fell 23 percent.

Shares of base and precious metal miners were lower amid weakness in underlying commodities.

Goldcorp was down 86 Canadian cents, or 3 percent, at C$27.43. Teck Cominco fell C$1.70, or 2 percent, to C$85.50

The consumer staples sector rose 3.1 percent on news that Empire aims to take Sobeys private by buying up the stock it doesn't already own.

Empire owns 72.1 percent of Sobeys' outstanding shares and is offering C$58 a share in cash for the minority stake.

Shares of Empire jumped C$1.39, or 3.5 percent, to C$41.65, while Sobeys soared C$19.45, or 52 percent, to C$57.25.

The news helped boost other companies in the sector including Loblaw, which rose C$2.60, or 5.2 percent, to C$52.85, and Metro, up C$1.85, or 4.9 percent, at C$39.85.