PMID- 8702607
OWN - NLM
STAT- MEDLINE
DCOM- 19960916
LR  - 20210210
IS  - 0021-9258 (Print)
IS  - 0021-9258 (Linking)
VI  - 271
IP  - 32
DP  - 1996 Aug 9
TI  - A conformational rearrangement upon binding of IgE to its high affinity receptor.
PG  - 19256-63
AB  - One of the critical steps in the allergic reaction is the binding of 
      immunoglobulin E (IgE) to its high affinity receptor (FcepsilonRI). FcepsilonRI 
      is a tetrameric complex composed of an alpha-chain, a beta-chain, and a dimeric 
      gamma-chain. The extracellular portion of the alpha-chain (alpha-t) is sufficient 
      for the binding of IgE. The Fc portion of IgE contains two copies of the 
      FcepsilonRI binding sites. In contrast, the binding stoichiometry is 1:1. 
      Previously, it was hypothesized that the binding of FcepsilonRI to IgE results in 
      a conformational change in IgE that precludes the binding of a second molecule 
      (Presta, L., Shields, R., O'Connel, L., Lahr, S., Porter, J. , Gorman, C., and 
      Jardieu, P.(1994) J. Biol. Chem. 269, 26368-26373). Here we characterize the 
      secondary structure of IgE and alpha-t and analyze their interaction by circular 
      dichroism spectroscopy. Binding experiments show that when IgE interacts with 
      alpha-t there is a 15-26% decrease of the negative ellipticity at 217 nm. 
      Together, the absence of an alpha-helix element in alpha-t and the small 
      contribution of alpha-t to the spectra of the complex indicate that upon binding, 
      a major conformational rearrangement must occur on IgE. In addition, we analyze 
      the thermal unfolding of alpha-t, IgE, and their complex. Despite the several 
      domains that constitute IgE and alpha-t, these molecules unfold cooperatively 
      with two-state kinetics.
FAU - Sechi, S
AU  - Sechi S
AD  - Molecular Allergy and Immunology Section, NIAID, National Institutes of Health, 
      Rockville, Maryland 20852, USA.
FAU - Roller, P P
AU  - Roller PP
FAU - Willette-Brown, J
AU  - Willette-Brown J
FAU - Kinet, J P
AU  - Kinet JP
LA  - eng
PT  - Journal Article
PL  - United States
TA  - J Biol Chem
JT  - The Journal of biological chemistry
JID - 2985121R
RN  - 0 (Receptors, IgE)
RN  - 37341-29-0 (Immunoglobulin E)
SB  - IM
MH  - Animals
MH  - CHO Cells
MH  - Circular Dichroism
MH  - Cricetinae
MH  - Humans
MH  - Immunoglobulin E/*metabolism
MH  - Protein Binding
MH  - Protein Conformation
MH  - Protein Folding
MH  - Receptors, IgE/chemistry/isolation & purification/*metabolism
MH  - Spectrophotometry, Ultraviolet
EDAT- 1996/08/09 00:00
MHDA- 1996/08/09 00:01
CRDT- 1996/08/09 00:00
PHST- 1996/08/09 00:00 [pubmed]
PHST- 1996/08/09 00:01 [medline]
PHST- 1996/08/09 00:00 [entrez]
AID - S0021-9258(19)84358-2 [pii]
AID - 10.1074/jbc.271.32.19256 [doi]
PST - ppublish
SO  - J Biol Chem. 1996 Aug 9;271(32):19256-63. doi: 10.1074/jbc.271.32.19256.