Brookfield Office Properties Inc. has closed the sale of one of the tallest office towers in downtown Denver, 1801, California St. Brookfield, with a group of investors, bought the 28-year-old skyscraper for $215 million from PSEG Energy Holdings, a subsidiary of the Newark, N.J.-based Public Service Enterprises Group Inc. Monroe, La.-based CenturyLink holds the master lease on the building until June 30. When the lease expires, Brookfield plans to make capital improvements to the building and will look to fill several hundred thousand vacant square feet of office space.