Catalyzes the condensation of (R)-4-phosphopantoate and beta-alanine to 4'-phosphopantothenate in the CoA biosynthesis pathway. (R)-4-phosphopantoate + ATP + beta-alanine = (R)-4'-phosphopantothenate + AMP + diphosphate + H(+) Cofactor biosynthesis; coenzyme A biosynthesis. Homodimer. Was originally thought to have pantothenate synthetase (PS) activity. Purified recombinant protein shows no PS activity on its own, but the enzyme enables substantial synthesis of 4'-phosphopantothenate from beta-alanine, pantoate and ATP when coupled with E. coli pantothenate kinase. ADP, but not AMP, was detected as a coproduct of the coupled reaction. Belongs to the archaeal phosphopantothenate synthetase family.