ManB is a bacterial phosphomannomutase (PMM) that catalyzes the conversion of mannose 6-phosphate to mannose-1-phosphate in the second of three steps in the GDP-mannose pathway, in which GDP-D-mannose is synthesized from fructose-6-phosphate. In Mycobacterium tuberculosis, the causative agent of tuberculosis, PMM is involved in the biosynthesis of mannosylated lipoglycans that participate in the association of mycobacteria with host macrophage phagocytic receptors. ManB belongs to the the alpha-D-phosphohexomutase superfamily which includes several related enzymes that catalyze a reversible intramolecular phosphoryl transfer on their sugar substrates. Other members of this superfamily include the phosphoglucomutases (PGM1 and PGM2), phosphoglucosamine mutase (PNGM), phosphoacetylglucosamine mutase (PAGM), the bacterial phosphoglucosamine mutase GlmM, and the bifunctional phosphomannomutase/phosphoglucomutase (PMM/PGM). Each of these enzymes has four domains with a centrally located active site formed by four loops, one from each domain. All four domains are included in this alignment model.