<p>The Stirrup domain, found in the prokaryotic protein ribonucleotide reductase, has a molecular mass of 9 kDa and is folded into an alpha/beta structure. It allows for binding of the reductase to DNA via electrostatic interactions, since it has a predominance of positive charges distributed on its surface [<cite idref="PUB00024294"/>]. </p> Ribonucleotide reductase, stirrup