The Mycobacterium tuberculosis open reading frame Rv3214, annotated as a cofactor-dependent phosphoglycerate mutase, has been cloned and expressed as an N-terminally His-tagged protein. Tagged, untagged and selenomethionine-labelled forms of Rv3214 (EntD) have been purified using nickel-affinity chromatography and gel filtration. The selenomethionine-labelled crystals diffracted to 2.15 A resolution and belong to space group P2(1), with unit-cell parameters a = 44.36, b = 79.03, c = 52.85 A, beta = 109.11 degrees. There are two molecules of molecular weight 21,948 Da per asymmetric unit.