02366nas a2200277   4500008004100000022001400041245009100055210006900146260009000215300001400305490000800319520140000327653003101727653001501758653002701773653002801800653001401828100002101842700001501863700001701878700002001895700001701915700002101932700001901953856011601972       2015                        eng d  a0022-283600aAtomic-resolution structures of the APC/C subunits Apc4 and the Apc5 N-terminal domain0 aAtomicresolution structures of the APCC subunits Apc4 and the Ap  a24-28 OVAL RD, LONDON NW1 7DX, ENGLANDbACADEMIC PRESS LTD- ELSEVIER SCIENCE LTDcOCT  a3300-33150 v4273 a<p>Many essential biological processes are mediated by complex molecular machines comprising multiple subunits. Knowledge on the architecture of individual subunits and their positions within the overall multimeric complex is key to understanding the molecular mechanisms of macromolecular assemblies. The anaphase-promoting complex/cyclosome (APC/C) is a large multisubunit complex that regulates cell cycle progression by ubiquitinating cell cycle proteins for proteolysis by the proteasome. The holo-complex is composed of 15 different proteins that assemble to generate a complex of 20 subunits. Here, we describe the crystal structures of Apc4 and the N-terminal domain of Apc5 (Apc5(N)). Apc4 comprises a WD40 domain split by a long alpha-helical domain, whereas Apc5(N) has an alpha-helical fold. In a separate study, we had fitted these atomic models to a 3.6-angstrom-resolution cryo-electron microscopy map of the APC/C. We describe how, in the context of the APC/C, regions of Apc4 disordered in the crystal assume order through contacts to Apc5, whereas Apc5(N) shows small conformational changes relative to its crystal structure. We discuss the complementary approaches of high-resolution electron microscopy and protein crystallography to the structure determination of subunits of multimeric complexes. (c) 2015 MRC Laboratory of Molecular Biology. Published by Elsevier Ltd.</p>10aanaphase-promoting complex10acell cycle10amultisubunit structure10aprotein crystallography10aubiquitin1 aCronin, Nora, B.1 aYang, Jing1 aZhang, Ziguo1 aKulkarni, Kiran1 aChang, Leifu1 aYamano, Hiroyuki1 aBarford, David  uhttps://library.ncl.res.in/content/atomic-resolution-structures-apcc-subunits-apc4-and-apc5-n-terminal-domain-0