This is the N-terminal domain of bacterial AMP nucleoside phosphorylase (AMNp). The N- and C-termini form distinct domains which intertwine with each other to form a stable monomer which associates with five other monomers to yield the active hexamer. The N-terminus consists of a long helix and a four-stranded sheet with a novel topology. The C-terminus binds the nucleoside whereas the N-terminus acts as the enzymatic regulatory domain. AMNp (EC:126.96.36.199) catalyzes the hydrolysis of AMP to form adenine and ribose 5-phosphate. thereby regulating intracellular AMP levels.