title: Crystallization and preliminary X-ray structural studies of a high-affinity CD8alphaalpha co-receptor to pMHC.
abstract: The class I CD8 positive T-cell response is involved in a number of conditions in which artificial down-regulation and control would be therapeutically beneficial. Such conditions include a number of autoimmune diseases and graft rejection in transplant patients. Although the CD8 T-cell response is dominated by the TCR-pMHC interaction, activation of T cells is in most cases also dependent on a number of associated signalling molecules. Previous work has demonstrated the ability of one such molecule (CD8) to act as an antagonist to T-cell activation if added in soluble form. Therefore, a high-affinity mutant CD8 (haCD8) has been developed with the aim of developing a therapeutic immunosuppressor. In order to fully understand the nature of the haCD8 interaction, this protein was crystallized using the sitting-drop vapour-diffusion method. Single haCD8 crystals were cryocooled and used for data collection. These crystals belonged to space group P6(4)22 (assumed by similarity to the wild type), with unit-cell parameters a = 101.08, c = 56.54 A. VM calculations indicated one molecule per asymmetric unit. A 2 A data set was collected and the structure is currently being determined using molecular replacement.
authors.affiliation: Nuffield Department of Clinical Medicine, John Radcliffe Hospital, Oxford University, Oxford OX3 9DU, England.
authors.forename: David K
authors.initials: DK
authors.lastname: Cole
authors.forename: Pierre J
authors.initials: PJ
authors.lastname: Rizkallah
authors.forename: Malkit
authors.initials: M
authors.lastname: Sami
authors.forename: Nikolai M
authors.initials: NM
authors.lastname: Lissin
authors.forename: Feng
authors.initials: F
authors.lastname: Gao
authors.forename: John I
authors.initials: JI
authors.lastname: Bell
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Boulter
authors.forename: Meir
authors.initials: M
authors.lastname: Glick
authors.forename: Anne Lise
authors.initials: AL
authors.lastname: Vuidepot
authors.forename: Bent K
authors.initials: BK
authors.lastname: Jakobsen
authors.forename: George F
authors.initials: GF
authors.lastname: Gao
mesh_terms: D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D003001:Cloning, Molecular; D003460:Crystallization; D006801:Humans; D008285:Major Histocompatibility Complex; D011487:Protein Conformation; D011489:Protein Denaturation; D017510:Protein Folding; D011948:Receptors, Antigen, T-Cell / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism
chemical_list: C067361:CD8 receptor; D011948:Receptors, Antigen, T-Cell; D011994:Recombinant Proteins