Wachovia Capital Partners, the private equity investment arm of Wachovia bank, and M/C Venture Partners have teamed up to purchase National Grid Wireless US in a deal worth $290 million.

National Grid Wireless, which is part of a European firm, operates 350 communications towers and more than 1,100 miles of unused fiber optic networks as well as outdoor distributed antenna systems. Its operations are focused in the northeast. The firm’s headquarters are located in Boxborough, Mass.

The company has 120 employees and will continue to be led by Doug Wiest, its current chief executive officer.

M/C Venture Partners is a venture capital firm based in Boston.