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Title: Building a pseudo-atomic model of the anaphase-promoting complex

This article describes an example of molecular replacement in which atomic models are used to interpret electron-density maps determined using single-particle electron-microscopy data. The anaphase-promoting complex (APC/C) is a large E3 ubiquitin ligase that regulates progression through specific stages of the cell cycle by coordinating the ubiquitin-dependent degradation of cell-cycle regulatory proteins. Depending on the species, the active form of the APC/C consists of 14–15 different proteins that assemble into a 20-subunit complex with a mass of approximately 1.3 MDa. A hybrid approach of single-particle electron microscopy and protein crystallography of individual APC/C subunits has been applied to generate pseudo-atomic models of various functional states of the complex. Three approaches for assigning regions of the EM-derived APC/C density map to specific APC/C subunits are described. This information was used to dock atomic models of APC/C subunits, determined either by protein crystallography or homology modelling, to specific regions of the APC/C EM map, allowing the generation of a pseudo-atomic model corresponding to 80% of the entire complex.
Authors:
; ; ; ; ;  [1]
  1. Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London SW3 6JB (United Kingdom)
Publication Date:
OSTI Identifier:
22347836
Resource Type:
Journal Article
Resource Relation:
Journal Name: Acta Crystallographica. Section D: Biological Crystallography; Journal Volume: 69; Journal Issue: Pt 11; Other Information: PMCID: PMC3817697; PMID: 24189235; PUBLISHER-ID: ba5200; OAI: oai:pubmedcentral.nih.gov:3817697; Copyright (c) Kulkarni et al. 2013; This is an open-access article distributed under the terms of the Creative Commons Attribution Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
Denmark
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ATOMS; CRYSTALLOGRAPHY; CRYSTALS; DENSITY; ELECTRON DENSITY; ELECTRON MICROSCOPY; ELECTRONS; HYBRIDIZATION; MASS