EC Number   |
|---|
   6.5.1.8 | crystal structures of RtcB in complex with Mn2+ alone and together with a covalently bound GMP, to 1.6 A and 2.3 A resolution, respectively. The RtcB/Mn2+ structure shows two Mn2+ ions at the active site, and an array of sulfate ions nearby that indicate the binding sites of the RNA phosphate backbone. The structure of the RtcB-GMP/Mn2+ complex reveals the detailed geometry of guanylylation of histidine 404. The enzyme's substrate-induced GTP binding site and the putative reactive RNA ends are in the vicinity of the binuclear Mn2+ active center |
| 6.5.1.8 | in complex with GDP and Mg2+, sitting drop vapor diffusion method, using 0.2 M sodium dihydrogen phosphate, 20% (w/v) PEG3350 |
| 6.5.1.8 | three structures of RtcB complexes that capture snapshots along the entire guanylylation pathway. RtcB in complex with Mn(II) and GTP analogue guanosine 5'-(alpha-thio)-triphosphate shows that Mn1 is poised to stabilize the pentavalent transition state of guanylylation while a second manganese ion (Mn2) is coordinated to a nonbridging oxygen of the gamma-phosphoryl group. The diphosphate leaving group of 5'-(alpha-thio)-triphosphate is oriented apically to His404 with the epsilon nitrogen poised for in-line attack on the alpha phosphorus atom. The structure of RtcB in complex with 5'-(alpha-thio)-triphosphate also reveals the network of hydrogen bonds that recognize GTP and shows significant conformational changes accompanying the binding of the cofactor. A structure of the enzymic histidine-GMP intermediate depicts the end of the guanylylation pathway |
