The L-type (legume-type) lectins are a highly diverse family of carbohydrate binding proteins that generally display no enzymatic activity toward the sugars they bind. This family includes arcelin, concanavalinA, the lectin-like receptor kinases, the ERGIC-53/VIP36/EMP46 type1 transmembrane proteins, and an alpha-amylase inhibitor. L-type lectins have a dome-shaped beta-barrel carbohydrate recognition domain with a curved seven-stranded beta-sheet referred to as the "front face" and a flat six-stranded beta-sheet referred to as the "back face". This domain homodimerizes so that adjacent back sheets form a contiguous 12-stranded sheet and homotetramers occur by a back-to-back association of these homodimers. Though L-type lectins exhibit both sequence and structural similarity to one another, their carbohydrate binding specificities differ widely.