Bank of New York Mellon is selling its Art Deco headquarters tower on Wall Street for $585 million to a venture led by developer Harry Macklowe, becoming the latest financial firm to pare back its Manhattan real estate. The bank plans to vacate the 1.1 million-square-foot building and is in negotiations with landlord Brookfield Office Properties to lease more than 400,000 square feet of space at Brookfield Place by the World Trade Center. The sale comes as institutions across the banking sector have been stepping up efforts to cut costs, particularly in real estate. Many have cut back New York head counts, and most banks are packing more employees into denser, more efficient offices. In a statement confirming the sale, Gerald Hassell, the bank’s chief executive, said the sale will result in a solid financial gain. The sale also will enable BNY Mellon to consolidate in New York and increase the efficiency of its workspace, he said.