DMJM will take 125,000 sf for 15 years at Shuwa Corp.'s twin-towered Arco Plaza on Flower Street. The company will move from its longtime Westside home at One Park Plaza in late September, bringing more than 500 workers with it.

Though DMJM and Shuwa officials won't disclose financial terms, sources familiar with the transaction say the lease is probably worth between $45 million and $50 million. GlobeSt.com and its sister print publication, Real Estate Southern California, reported earlier this year that the deal appeared imminent.

Several relatively large leases have been signed in the CBD over the past several months, but none as large as the 125,000 sf taken by DMJM. Yet, the deal's importance goes far beyond sheer size.

Local brokers say DMJM's decision to choose the central business district helps to re-certify its status as a prime corporate headquarters location, a reputation it lost when several large employers moved out during the recession and ensuing wave of mergers that dominated much of the 1990s. The architectural and engineering firm's 500-plus workers will boost the CBD's struggling businesses, from restaurants and bars to copy centers and dry cleaners.

The deal also marks another milestone at Arco Plaza, a 2.2-million sf complex that still stands more than 30% vacant but whose fortunes seem to be improving. Tokyo-based Shuwa Corp. hired Cushman & Wakefield Inc. to market the building earlier this year after handling leasing duties itself since it bought the complex in 1986. DMJM was hired to renovate the building's lobby, remodel suites and handle tenant improvements.

A Cushman Realty Corp. team of Brian Ulf, C. Edward Simpson and Andrew Goodman represented DMJM in its lease negotiations. Shuwa's Thomas Kibler negotiated for the owner.