Selenium is an important nutrient that needs to be regulated since lack of the nutrient leads to cell abnormalities and high concentrations are toxic. SeBP regulates the level of free selenium in the cell by sequestering the nutrient during transport. SeBP acts as a pentamer and delivers the selenium to the selenophosphate synthetase enzyme [1]. Each subunit is composed of an alpha helix on top of a four stranded twisted ss sheet, stabilised by hydrogen bonds [1].

1: Solution NMR structure of selenium-binding protein from methanococcus vannielii. Suzuki M, Lee DY, Inyamah N, Stadtman TC, Tjandra N; J Biol Chem 2008; [Epub ahead of print] PMID:18650445