SAN FRANCISCO-Digital Realty Trust Inc. has paid $85 million for a 155,000-square-foot data center in downtown San Francisco. The announcement of the Bay Area deal coincides with the purchase of a similar building in Atlanta, near the Hartsfield-Jackson Atlanta International Airport, for $63 million.

Digital Realty’s new San Francisco building has at least one obvious appeal to the publicly-traded real estate company: The data center, which is a fully leased, multi-tenant building, sits back-to-backwith the company’s existing "server farm" at 365 Main St.

The purchase gives the company a greater "critical mass" in telecommunications and colocator space in San Francisco, according to Digital Realty vice president Pamela Garibaldi. With the purchase of 360 Spear, the company currently has three telecom properties in the city, including 200 Paul. "There's very limited data center space in San Francico," she adds.

Although the Spear Street facility is fully leased, "there is the potential for us to convert some of the space for our growing colocation business," Garibaldi says.

Digital Realty invests primarily in data centers, which provide space for Internet and telecommunications equipment. Typical tenants include information technology companies, Internet-related businesses, manufacturing firms and financial service firms, according to the company.

With the exception of three properties owned in joint ventures, Digital Realty currently owns 100 properties comprised of 17.9 million square feet. This also includes 2.1 million square feet for redevelopment. The company’s property holdings are located in Australia, Europe, North America and Singapore.