This family represents 2,3-bisphosphoglycerate-independent phosphoglycerate mutase (iPGAM), a metalloenzyme found particularly in archaea and some eubacteria, which catalyzes the interconversion of 2-phosphoglycerate and 3-phosphoglycerate in the reaction: [(2R)-2-phosphoglycerate = (2R)-3-phosphoglycerate] (EC 5.4.2.12).