Denver’s newest skyscraper will be home to one of the city’s most recognizable home-grown businesses by the end of next year. Chipotle Mexican Grill announced Wednesday that it has a signed a 15-year lease to house its corporate headquarters in the nearly finished 1144 Fifteenth building at 1144 15th St. downtown beginning in late 2018. The fast casual Mexican food chain, operating more than 2,350 restaurants worldwide, currently does its corporate business out of offices in buildings at 1401 Wynkoop St.