legume-like lectins: ERGIC-53, ERGL, VIP36, VIPL, EMP46, and EMP47
The legume-like (leg-like) lectins are eukaryotic intracellular sugar transport proteins with a carbohydrate recognition domain similar to that of the legume lectins. This domain binds high-mannose-type oligosaccharides for transport from the endoplasmic reticulum to the Golgi complex. These leg-like lectins include ERGIC-53, ERGL, VIP36, VIPL, EMP46, EMP47, and the UIP5 (ULP1-interacting protein 5) precursor protein. Leg-like lectins have different intracellular distributions and dynamics in the endoplasmic reticulum-Golgi system of the secretory pathway and interact with N-glycans of glycoproteins in a calcium-dependent manner, suggesting a role in glycoprotein sorting and trafficking. 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.