A joint venture of Hines affiliate Urban Pacific Development, LLC and Goldman Sachs affiliate Broad Street Principal Investments, L.L.C. is acquiring Parcel F, the last development site in San Francisco zoned for a height taller than 550 feet. The venture, F4 Transbay Partners LLC has placed a $10 million deposit on the purchase, which includes a $15 million premium in the event of an assemblage of the property with an adjoining lot at 540 Howard.