1xmw
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CD3 EPSILON AND DELTA ECTODOMAIN FRAGMENT COMPLEX IN SINGLE-CHAIN CONSTRUCT
OverviewOverview
Invariant CD3 subunit dimers (CD3epsilongamma, CD3epsilondelta, and, CD3zetazeta) are the signaling components of the alphabeta T cell receptor, (TCR). The recently solved structure of murine CD3epsilongamma revealed a, unique side-to-side interface and central beta-sheets conjoined between, the two C2-set Ig-like ectodomains, with the pairing of the parallel G, strands implying a potential concerted piston-type movement for signal, transduction. Although CD3gamma and CD3delta each dimerize with, CD3epsilon, there are differential CD3 subunit requirements for receptor, assembly and signaling among T lineage subpopulations, presumably mandated, by structural differences. Here we present the solution structure of the, heterodimeric CD3epsilondelta complex. Whereas the CD3epsilon subunit, conformation is virtually identical to that in CD3epsilongamma, the, CD3delta ectodomain adopts a C1-set Ig fold, with a narrower GFC front, face beta-sheet that is more parallel to the ABED back face than those, beta-sheets in CD3epsilon and CD3gamma. The dimer interface between, CD3delta and CD3epsilon is highly conserved among species and of similar, character to that in CD3epsilongamma. Glycosylation sites in CD3delta are, arranged such that the glycans may point away from the membrane, consistent with a model of TCR assembly that allows the CD3delta chain to, be in close contact with the TCR alpha-chain. This and many other, structural and biological features provide a basis for modeling putative, TCR/CD3 extracellular domain associations. The fact that the two clusters, of transmembrane helices, namely, the three CD3epsilon-CD3gamma-TCRbeta, segments and the five CD3epsilon-CD3delta-TCRalpha-CD3zeta-CD3zeta, segments, are presumably centered beneath the G strand-paired CD3, heterodimers has important implications for TCR signaling.
About this StructureAbout this Structure
1XMW is a Single protein structure of sequence from Mus musculus, ovis aries. Full crystallographic information is available from OCA.
ReferenceReference
Solution structure of the CD3epsilondelta ectodomain and comparison with CD3epsilongamma as a basis for modeling T cell receptor topology and signaling., Sun ZY, Kim ST, Kim IC, Fahmy A, Reinherz EL, Wagner G, Proc Natl Acad Sci U S A. 2004 Nov 30;101(48):16867-72. Epub 2004 Nov 19. PMID:15557001
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