Metal-binding domains and the metal selectivity of the vanadium(IV)-binding protein VBP-129 in blood plasma

► We generated deletion and point mutants of a vanadium-binding protein VBP-129. ► We found that VBP-129, and its internal partial proteins, VBP-N52 and VBP-Int55, bind to 6, 3 and 2 VIV ions, respectively. ► ESR spectrum analysis indicated a N2O2 coordination geometry.