title: Cloning, expression, and crystallization of the V delta domain of a human gamma delta T-cell receptor.
abstract: T-lymphocytes recognize a wide variety of antigens through highly diverse cell-surface glycoproteins known as T-cell receptors (TCRs). These disulfide-linked heterodimers are composed of alpha and beta or gamma and delta polypeptide chains consisting of variable (V) and constant (C) domains non-covalently associated with at least four invariant chains to form the TCR-CD3 complex. It is well established that alpha beta TCRs recognize antigen in the form of peptides bound to molecules of the major histocompatibility complex (MHC); furthermore, information on the three-dimensional structure of alpha beta TCRs has recently become available through X-ray crystallography. In contrast, the antigen specificity of gamma delta TCRs is much less well understood and their three-dimensional structure is unknown. We have cloned the delta chain of a human TCR specific for the MHC class I HLA-A2 molecule and expressed the V domain as a secreted protein in the periplasmic space of Escherichia coli. Following affinity purification using a nickel chelate adsorbent, the recombinant V delta domain was crystallized in a form suitable for X-ray diffraction analysis. The crystals are orthorhombic, space group P2(1)2(1)2 with unit cell dimensions a = 69.9, b = 49.0, c = 61.6 A. and diffract to beyond 2.3 A resolution. The ability of a V delta domain produced in bacteria to form well-ordered crystals strongly suggests that the periplasmic space can provide a suitable environment for the correct in vivo folding of gamma delta TCRs.
authors.affiliation: Center for Advanced Research in Biotechnology, University of Maryland Biotechnology Institute, Rockville 20850, USA.
authors.forename: M I
authors.initials: MI
authors.lastname: Lebedeva
authors.forename: B A
authors.initials: BA
authors.lastname: Fields
authors.forename: H
authors.initials: H
authors.lastname: Spits
authors.forename: G
authors.initials: G
authors.lastname: Panchamoorthy
authors.forename: M B
authors.initials: MB
authors.lastname: Brenner
authors.forename: R A
authors.initials: RA
authors.lastname: Mariuzza
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D003460:Crystallization; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D006801:Humans; D007135:Immunoglobulin Variable Region / Q000737:chemistry / Q000235:genetics; D008969:Molecular Sequence Data; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000737:chemistry / Q000235:genetics*
chemical_list: D007135:Immunoglobulin Variable Region; D016692:Receptors, Antigen, T-Cell, gamma-delta