Crystallization and functional analysis of a soluble deglycosylated form of the human costimulatory molecule B7-1.

Journal article

The interactions of B7-1 with CD28 and CTLA-4 modulate the course of human immune responses, making B7-1 an important target for developing structure-based therapeutics. B7-1 is, however, one of the most heavily glycosylated proteins found at the leukocyte cell surface, complicating the structural analysis of this molecule. Methods for the production, crystallization and selenomethionine labelling of a soluble deglycosylated form of this molecule are described. The protein readily forms both tetragonal plate and bipyramidal crystals belonging to space groups I4(1)22, with unit-cell parameters a = b = 56.9, c = 298.7 A, and P4(1)22 (or P4(3)22), with unit-cell parameters a = b = 89.0, c = 261.9 A, respectively. The I4(1)22 and primitive crystal forms diffract to 2.7 and 3.5 A, respectively. Surface plasmon resonance-based assays indicate that the ligand-binding properties of sB7-1 are unaffected by deglycosylation. Since none of the methods relied on any special structural properties of sB7-1, it is proposed that this novel combination of procedures could in principle be adapted to the systematic analysis of many other glycoproteins of structural or functional interest.

Authors: Davis, S; Ikemizu, S; Collins, A; Fennelly, J; Harlos, K

• Publication status: Published
• Journal: Acta crystallographica. Section D, Biological crystallography
• Volume: 57
• Issue: Pt 4
• Pages: 605-608
• Publication date: 2001-04-01
• DOI: 10.1107/s0907444901001895
• EISSN: 1399-0047
• ISSN: 0907-4449
• Language: English
• Keywords: Protein Binding; Glycosylation; Selenomethionine; X-Ray Diffraction; Surface Plasmon Resonance; CTLA-4 Antigen; Antigens, CD80; Humans; Immunoconjugates; Crystallization; Solubility; Antigens, Differentiation; Antigens, CD; Recombinant Fusion Proteins; Antigens, CD28