MPG Office Trust Inc. on Monday said that it has entered into an agreement with its joint venture partner at downtown L.A.’s One California Plaza and other properties that will enable the partner to sell its interest to a Boston private investment firm.

Charter Hall Office REIT of Sydney, Australia plans to transfer its interest to affiliates of Beacon Capital Partners LLC. The new MPG-Beacon joint venture will continue to own One California Plaza, Cerritos Corporate Center in Cerritos and Stadium Gateway in Anaheim. MPG will continue to have a 20 percent interest in the joint venture after the deal closes.

MPG, which has been selling off non-core properties, particularly in Orange County, said the deal calls for the existing MPG-Charter joint venture to sell its interests in Denver’s Wells Fargo Center and the San Diego Tech Center to affiliates of Beacon before the changeover. After the change, the MPG-Beacon joint venture will work to sell Stadium Gateway.

MPG expects to receives $45 million in net proceeds from the transactions (in addition to any Stadium Gateway sale), which it plans to use for general corporate purposes.

MPG shares closed up 4 cents, or 1.7 percent, to $2.39 on the New York Stock Exchange.