TY - JOUR
T1 - Tangled up in knots
T2 - Structures of inactivated forms of E. coli class Ia ribonucleotide reductase
AU - Zimanyi, Christina M.
AU - Ando, Nozomi
AU - Brignole, Edward J.
AU - Asturias, Francisco J.
AU - Stubbe, Joanne
AU - Drennan, Catherine L.
N1 - Funding Information:
We thank Jun Wang for help with initial crystallization experiments. For assistance with SAXS and crystallographic data collection at Cornell High Energy Synchrotron Source (CHESS), we thank Dr. Mackenzie Firer-Sherwood and Rebekah Bjork and CHESS scientists Drs. Chae Un Kim, Arthur Woll, and Richard Gillilan. We thank Prof. Sol Gruner (Cornell University) for access to SAXS equipment. CHESS is supported by the National Science Foundation (NSF) and the National Institute of General Medical Sciences (NIGMS) via NSF award DMR-0936384; the MacCHESS resource is supported by NIGMS award GM103485. Crystallographic data were also collected at the Advanced Photon Source (APS) on the Northeastern Collaborative Access Team beamlines, which are supported by NCRR award RR-15301 and NIGMS award GM103403-10. The APS is also supported by the United States Department of Energy under Contract No. DE-AC02-06CH11357. Electron microscopy was performed at the National Resource for Automated Molecular Microscopy, which is supported by the National Institutes of Health (NIH) though the NCRR P41 program (RR017573). This work was supported by NIH grants T32GM08334 (to C.M.Z.), F32GM090486 (to N.A.), F32DK080622 (to E.J.B.), GM67167 (to F.J.A.), P30-ES002109 (to C.L.D.), and GM29595 (to J.S.). C.L.D. is a Howard Hughes Medical Institute Investigator.
PY - 2012/8/8
Y1 - 2012/8/8
N2 - Ribonucleotide reductases (RNRs) provide the precursors for DNA biosynthesis and repair and are successful targets for anticancer drugs such as clofarabine and gemcitabine. Recently, we reported that dATP inhibits E. coli class Ia RNR by driving formation of RNR subunits into α4β 4 rings. Here, we present the first X-ray structure of a gemcitabine-inhibited E. coli RNR and show that the previously described α4β4 rings can interlock to form an unprecedented (α4β4)2 megacomplex. This complex is also seen in a higher-resolution dATP-inhibited RNR structure presented here, which employs a distinct crystal lattice from that observed in the gemcitabine-inhibited case. With few reported examples of protein catenanes, we use data from small-angle X-ray scattering and electron microscopy to both understand the solution conditions that contribute to concatenation in RNRs as well as present a mechanism for the formation of these unusual structures.
AB - Ribonucleotide reductases (RNRs) provide the precursors for DNA biosynthesis and repair and are successful targets for anticancer drugs such as clofarabine and gemcitabine. Recently, we reported that dATP inhibits E. coli class Ia RNR by driving formation of RNR subunits into α4β 4 rings. Here, we present the first X-ray structure of a gemcitabine-inhibited E. coli RNR and show that the previously described α4β4 rings can interlock to form an unprecedented (α4β4)2 megacomplex. This complex is also seen in a higher-resolution dATP-inhibited RNR structure presented here, which employs a distinct crystal lattice from that observed in the gemcitabine-inhibited case. With few reported examples of protein catenanes, we use data from small-angle X-ray scattering and electron microscopy to both understand the solution conditions that contribute to concatenation in RNRs as well as present a mechanism for the formation of these unusual structures.
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U2 - 10.1016/j.str.2012.05.009
DO - 10.1016/j.str.2012.05.009
M3 - Article
C2 - 22727814
AN - SCOPUS:84864834779
SN - 0969-2126
VL - 20
SP - 1374
EP - 1383
JO - Structure
JF - Structure
IS - 8
ER -