PMID- 28844738 OWN - NLM STAT- In-Data-Review LR - 20171101 IS - 0006-3002 (Print) IS - 0006-3002 (Linking) VI - 1865 IP - 11 Pt A DP - 2017 Nov TI - Thermal sensitivity and flexibility of the Cepsilon3 domains in immunoglobulin E. PG - 1336-1347 LID - S1570-9639(17)30185-1 [pii] LID - 10.1016/j.bbapap.2017.08.005 [doi] AB - Immunoglobulin E (IgE) is the antibody that plays a central role in the mechanisms of allergic diseases such as asthma. Interactions with its receptors, FcepsilonRI on mast cells and CD23 on B cells, are mediated by the Fc region, a dimer of the Cepsilon2, Cepsilon3 and Cepsilon4 domains. A sub-fragment lacking the Cepsilon2 domains, Fcepsilon3-4, also binds to both receptors, although receptor binding almost exclusively involves the Cepsilon3 domains. This domain also contains the N-linked glycosylation site conserved in other isotypes. We report here the crystal structures of IgE-Fc and Fcepsilon3-4 at the highest resolutions yet determined, 1.75A and 2.0A respectively, revealing unprecedented detail regarding the carbohydrate and its interactions with protein domains. Analysis of the crystallographic B-factors of these, together with all earlier IgE-Fc and Fcepsilon3-4 structures, shows that the Cepsilon3 domains exhibit the greatest intrinsic flexibility and quaternary structural variation within IgE-Fc. Intriguingly, both well-ordered carbohydrate and disordered polypeptide can be seen within the same Cepsilon3 domain. A simplified method for comparing the quaternary structures of the Cepsilon3 domains in free and receptor-bound IgE-Fc structures is presented, which clearly delineates the FcepsilonRI and CD23 bound states. Importantly, differential scanning fluorimetric analysis of IgE-Fc and Fcepsilon3-4 identifies Cepsilon3 as the domain most susceptible to thermally-induced unfolding, and responsible for the characteristically low melting temperature of IgE. CI - Copyright (c) 2017 The Author(s). Published by Elsevier B.V. All rights reserved. FAU - Dore, Katy A AU - Dore KA AD - King's College London, Randall Division of Cell and Molecular Biophysics, New Hunt's House, London SE1 1UL, United Kingdom; Medical Research Council & Asthma UK Centre in Allergic Mechanisms of Asthma, London, United Kingdom. FAU - Davies, Anna M AU - Davies AM AD - King's College London, Randall Division of Cell and Molecular Biophysics, New Hunt's House, London SE1 1UL, United Kingdom; Medical Research Council & Asthma UK Centre in Allergic Mechanisms of Asthma, London, United Kingdom. FAU - Drinkwater, Nyssa AU - Drinkwater N AD - King's College London, Randall Division of Cell and Molecular Biophysics, New Hunt's House, London SE1 1UL, United Kingdom; Medical Research Council & Asthma UK Centre in Allergic Mechanisms of Asthma, London, United Kingdom. FAU - Beavil, Andrew J AU - Beavil AJ AD - King's College London, Randall Division of Cell and Molecular Biophysics, New Hunt's House, London SE1 1UL, United Kingdom; Medical Research Council & Asthma UK Centre in Allergic Mechanisms of Asthma, London, United Kingdom. FAU - McDonnell, James M AU - McDonnell JM AD - King's College London, Randall Division of Cell and Molecular Biophysics, New Hunt's House, London SE1 1UL, United Kingdom; Medical Research Council & Asthma UK Centre in Allergic Mechanisms of Asthma, London, United Kingdom. FAU - Sutton, Brian J AU - Sutton BJ AD - King's College London, Randall Division of Cell and Molecular Biophysics, New Hunt's House, London SE1 1UL, United Kingdom; Medical Research Council & Asthma UK Centre in Allergic Mechanisms of Asthma, London, United Kingdom. Electronic address: brian.sutton@kcl.ac.uk. LA - eng PT - Journal Article DEP - 20170824 PL - Netherlands TA - Biochim Biophys Acta JT - Biochimica et biophysica acta JID - 0217513 PMC - PMC5652521 OTO - NOTNLM OT - Antibody OT - Differential scanning fluorimetry OT - Domain flexibility OT - Glycosylation OT - Immunoglobulin E OT - Thermal unfolding EDAT- 2017/08/29 06:00 MHDA- 2017/08/29 06:00 CRDT- 2017/08/29 06:00 PHST- 2017/06/16 00:00 [received] PHST- 2017/07/14 00:00 [revised] PHST- 2017/08/07 00:00 [accepted] PHST- 2017/08/29 06:00 [pubmed] PHST- 2017/08/29 06:00 [medline] PHST- 2017/08/29 06:00 [entrez] AID - S1570-9639(17)30185-1 [pii] AID - 10.1016/j.bbapap.2017.08.005 [doi] PST - ppublish SO - Biochim Biophys Acta. 2017 Nov;1865(11 Pt A):1336-1347. doi: 10.1016/j.bbapap.2017.08.005. Epub 2017 Aug 24.