Cells enforce an ion curtain

摘要

It has been estimated that a third of all proteins require the help of metal ions to carry out their biological functions'. In most cases, these proteins obtain their metal cofactors directly from their surroundings, and so they need a mechanism to select the correct metal from the pool of metal ions to which they are exposed. On page 1138 of this issue, Tottey et al.2 show that bacteria can optimize this process by undertaking metal insertion in a cellular compartment with a favourable metal-ion composition, rather than in the compartment in which the protein functions.