TY - JOUR T1 - Unique ATP-cone-driven allosteric regulation of ribonucleotide reductase via the radical-generating subunit JF - bioRxiv DO - 10.1101/190033 SP - 190033 AU - Inna Rozman Grinberg AU - Daniel Lundin AU - Mahmudul Hasan AU - Mikael Crona AU - Venkateswara Rao Jonna AU - Christoph Loderer AU - Margareta Sahlin AU - Natalia Markova AU - Ilya Borovok AU - Gustav Berggren AU - Anders Hofer AU - Derek T Logan AU - Britt-Marie Sjöberg Y1 - 2017/01/01 UR - http://biorxiv.org/content/early/2017/09/17/190033.1.abstract N2 - Ribonucleotide reductases (RNRs) are key enzymes in DNA synthesis and repair, with sophisticated allosteric mechanisms controlling both substrate specificity and overall activity. In RNRs, the activity master-switch, the ATP-cone, has been found exclusively in the catalytic subunit. In two class I RNR subclasses whose catalytic subunit lacks the ATP-cone, we discovered ATP-cones in the radical-generating subunit. The ATP-cone in the Leewenhoekiella blandensis radical-generating subunit regulates activity via modifications of quaternary structure induced by binding of nucleotides. ATP induces enzymatically competent dimers, whereas dATP induces non-productive tetramers, resulting in different holoenzyme complexes. The tetramer forms solely by interactions between ATP-cones, as evidenced by a 2.45 Å crystal structure. We also present evidence for an MnIIIMnIV metal center. In summary, lack of an ATP-cone domain in the catalytic subunit was compensated by evolutionary capture of the domain by the radical-generating subunit. Our findings present a novel opportunity for dATP-regulation of engineered proteins. ER -