The use of propionate α-proton contact shifts as structural constraints

The use of pseudocontact shifts in the solution structure determination of low spin iron(III) hemoproteins allows one to estimate the contact shifts of heme protons. We investigate here the possibility of using the contact shifts of propionate α-protons as further structural constraints which would be precious since the number of the NOEs can be small. It is shown that the propionates of rat cytochrome b5 can indeed be refined.