Another law firm now calls Boston its home.

On Wednesday, Washington, D.C.-based Arnold & Porter opened an office on the 53rd floor of 200 Clarendon St. in the Back Bay in an effort to expand and strengthen its life sciences and healthcare practices in Boston, according to a press release. The firm didn't disclose the square footage of its office.

“While we have long had many Boston-based clients, this new office provides the opportunity to further integrate our firm into Boston’s vibrant life sciences and healthcare ecosystem,” Dan Kracov, co-chair of the firm's life sciences and healthcare regulatory practice and its life sciences practice, said in a statement. “Being in Boston will allow the team to closely collaborate with local industry players, strengthen our presence, and enhance our ability to serve clients.”

The firm hired three new attorneys as part of the expansion: Hemmie Chang, who will head the Boston office, and Josh Barlow and Fred Kelly, who will join as partners.

The expansion comes after the firm also opened an office in Amsterdam at the beginning of August, which also focuses on its life sciences practices. The firm also hired two partners along with that opening.

200 Clarendon St., previously known as John Hancock Tower, is one of the tallest buildings in Boston's skyline at 600 feet tall, and it has 1.7M SF of offices. Boston Properties acquired the tower in 2010.

In May, the Boston Business Journal reported that Bain Capital was looking to move its headquarters out of 200 Clarendon and search for as much as 400K SF in the city, the Boston Business Journal reported. The firm occupies roughly 270K SF at the tower and could consider staying and expanding there.

Arnold & Porter is the latest in a series of law firms and other professional services businesses to relocate to or expand in Boston.

Earlier this year, Covington & Burling LLP entered the Boston market, taking space at the The Chiofaro Co.'s One International Place near the city's waterfront, the BBJ reported.

Consulting firm Deloitte signed a 138K SF lease at MP Boston's Winthrop Center in July. Law firm Goulston & Storrs signed a 100K SF lease at Anchor Line Partners' $300M adaptive reuse One Post Office Square project in April, and private equity firm HarbourVest Partners signed for 250K SF at Fortis Property Group's One Lincoln office last year.