@article{2d37e69fdadb47e1aa4cca87924981ae,
title = "Substrate-Induced Allosteric Change in the Quaternary Structure of the Spermidine N-Acetyltransferase SpeG",
abstract = "The spermidine N-acetyltransferase SpeG is a dodecameric enzyme that catalyzes the transfer of an acetyl group from acetyl coenzyme A to polyamines such as spermidine and spermine. SpeG has an allosteric polyamine-binding site and acetylating polyamines regulate their intracellular concentrations. The structures of SpeG from Vibrio cholerae in complexes with polyamines and cofactor have been characterized earlier. Here, we present the dodecameric structure of SpeG from V. cholerae in a ligand-free form in three different conformational states: open, intermediate and closed. All structures were crystallized in C2 space group symmetry and contain six monomers in the asymmetric unit cell. Two hexamers related by crystallographic 2-fold symmetry form the SpeG dodecamer. The open and intermediate states have a unique open dodecameric ring. This SpeG dodecamer is asymmetric except for the one 2-fold axis and is unlike any known dodecameric structure. Using a fluorescence thermal shift assay, size-exclusion chromatography with multi-angle light scattering, small-angle X-ray scattering analysis, negative-stain electron microscopy and structural analysis, we demonstrate that this unique open dodecameric state exists in solution. Our combined results indicate that polyamines trigger conformational changes and induce the symmetric closed dodecameric state of the protein when they bind to their allosteric sites.",
keywords = "GNAT acetyltransf, allosteric site, asymmetric structure, dodecameric enzyme, spermidine/spermine",
author = "Filippova, {Ekaterina V.} and Steven Weigand and Jerzy Osipiuk and Olga Kiryukhina and Andrzej Joachimiak and Anderson, {Wayne F.}",
note = "Funding Information: We would like to thank Corey M. Janczak and the Keck Biophysics Facility at Northwestern University (Evanston, IL) for assistance with SEC-MALS data collection. We would like to thank Chi-Hao Luan and the High-Throughput Analysis Laboratory at Northwestern University (Evanston, IL) for assistance with FTS assay. The negative-stain EM analysis was performed at CryoEM Facility at Northwestern University (Evanston, IL). The EM research was supported in part by the Searle Leadership Fund for the Life Sciences at Northwestern University , established by the Searle Funds at The Chicago Community Trust . The SAXS and X-ray data collection for crystal structures was performed at the DND-CAT, LS-CAT and SBC-CAT beamlines, respectively, at the Advanced Photon Source Science User Facility operated for the U.S. Department of Energy, supported by the U.S. Department of Energy under Contract No. DE-AC02-06CH11357 . This project has been funded with Federal funds from the National Institute of Allergy and Infectious Diseases, National Institutes of Health, Department of Health and Human Services , under Contract Nos. HHSN272200700058C and HHSN272201200026C (W.F.A.) and the National Science Foundation grant MCB 1024945 (M.A.B.). Funding Information: We would like to thank Corey M. Janczak and the Keck Biophysics Facility at Northwestern University (Evanston, IL) for assistance with SEC-MALS data collection. We would like to thank Chi-Hao Luan and the High-Throughput Analysis Laboratory at Northwestern University (Evanston, IL) for assistance with FTS assay. The negative-stain EM analysis was performed at CryoEM Facility at Northwestern University (Evanston, IL). The EM research was supported in part by the Searle Leadership Fund for the Life Sciences at Northwestern University, established by the Searle Funds at The Chicago Community Trust. The SAXS and X-ray data collection for crystal structures was performed at the DND-CAT, LS-CAT and SBC-CAT beamlines, respectively, at the Advanced Photon Source Science User Facility operated for the U.S. Department of Energy, supported by the U.S. Department of Energy under Contract No. DE-AC02-06CH11357. This project has been funded with Federal funds from the National Institute of Allergy and Infectious Diseases, National Institutes of Health, Department of Health and Human Services, under Contract Nos. HHSN272200700058C andHHSN272201200026C(W.F.A.) and the National Science Foundation grant MCB 1024945 (M.A.B.). Publisher Copyright: {\textcopyright} 2015 The Authors.",
year = "2015",
month = jun,
day = "17",
doi = "10.1016/j.jmb.2015.09.013",
language = "English (US)",
volume = "427",
pages = "3538--3553",
journal = "Journal of Molecular Biology",
issn = "0022-2836",
publisher = "Academic Press Inc.",
number = "22",
}