A division of Boston’s Trans National Group Services has unveiled plans for a “transformative” 28-story, 340-foot residential tower at the site of its current headquarters, visible from the Massachusetts Turnpike, in Boston’s Fenway neighborhood.

Trans National Properties’ $250 million to $280 million project at 2 Charlesgate West would include up to 325 apartments and condos, plus retail and office space.

The curving glass and brownstone tower designed by Boston architect David Manfredi would be in the eastern “gateway” area of Fenway, where zoning allows greater flexibility for “architecturally distinctive” landmark buildings, ?according to TNP president Justin Krebs. TNP filed a letter of intent with the Boston Redevelopment Authority yesterday.

“Our proposed Charlesgate ?development can have a transformative impact on this part of the Fenway neighborhood,” Krebs said.

Trans National’s plans come as owner Steve Belkin, 69, who started more than 20 companies from the existing building ?acquired in 1976, is converting his holdings to real estate investments to benefit his children and philanthropic ?endeavors, Krebs said.

The tower would have up to 6,000 square feet of office space for Trans National, which would move most of its employees to 133 Federal St. in the Financial District or an adjacent tower planned for the Winthrop Square garage site should the city select it as the site’s developer, Krebs said.

About 10,000 square feet of ?retail space in the new Fenway tower would include a farm-to-table restaurant showcasing produce and hard cider from Natick’s Belkin Family Lookout Farm and a deli with locally sourced produce, baked goods and high-quality grab-and-go food. Just under 200 underground parking spaces would be included.

Trans National’s plans also call for art-driven ventures and other improvements to Ipswich Street, at the back of the proposed tower, which would be rebranded as the “Arts Fenway” corridor in partnership with local arts institutions and the Fenway Alliance.

“It amazes me how it’s essentially been abandoned,” Krebs said.

Trans National has committed to including at least half of its required 45 to 50 affordable housing units on-site and will work with Fenway Community Development Corp. and Fenway Studios, an artists’ cooperative on Ipswich Street, on off-site affordable units.