Legume lectin of view of protein structure. Despite the conserved structure of the legume lectin subunit, they can adopt a wide range of quaternary structures. The reason behind this remarkable variability is probably to be found in the interaction with multivalent ligands. Legume lectin The legume lectins (or L-type lectins) are a family of sugar-binding proteins or lectins found in the seeds and, in smaller amounts, in the roots, stems, leaves and bark of plants belonging to the Fabaceae family. The exact function of the legume lectins "in vivo" is unknown but they are probably involved in the defense of plants against
Beta-keratin whose flight capabilities have been questioned, would have had avian, but not feather, β-keratins. The small alvarezsaurid dinosaur "Shuvuuia deserti" shows evidence of a featherlike skin covering. Analysis by Schweitzer "et al." (1999) showed that these featherlike structures consisted of beta-keratin. There are two main forms of keratin, alpha-keratin and beta-keratin. Alpha-keratin is seen in humans and other mammals, beta-keratin is present in birds and reptiles. Beta-keratin is harder than alpha-keratin. Structurally alpha-keratin have alpha-helical coiled coil structure while beta-keratin have twisted beta sheet structure.bIn the case of β-sheets, this allows sterically-unhindered hydrogen bonding between the amino and carboxyl groups