The California Board of Equalization opened its new Santa Clarita regional center for businesses on Thursday. The state’s tax-gathering agency for businesses is closing its Van Nuys office on Sherman Way. Accounts served at that office will either be handled at the new office or the agency’s existing office in Glendale. The 22,000-square-foot Santa Clarita office at 25360 Magic Mountain Parkway features self-service computer kiosks that enable customers to conveniently register for a permit or license, file a return or make a payment. About 100 employees will move there from Van Nuys, when the San Fernando Valley office closes. The board collects about $56 billion annually in taxes and fees from businesses.