Comparison of the three-dimensional structures of a human Bence-Jones dimer crystallized on Earth and aboard US Space Shuttle Mission STS-95.
Crystals of a human (Sea) Bence-Jones dimer were produced in a capillary by vapor diffusion under microgravity conditions in the 9 day US Space Shuttle Mission STS-95. In comparison to ground-based experiments, nucleation was facile and spontaneous in space. Appearance of a very large (8 x 1.6 x 1.0 mm) crystal in a short time period is a strong endorsement for the use of microgravity to produce crystals sufficiently large for neutron diffraction studies. The Sea dimer crystallized in the orthorhombic space group P2(1)2(1)2(1), with a = 48.9 A, b = 85.2 A, and c = 114.0 A. The crystals grown in microgravity exhibited significantly lower mosaicities than those of ground-based crystals and the X-ray diffraction data had a lower overall B factor. Three-dimensional structures determined by X-ray analysis at two temperatures (100 and 293 K) were indistinguishable from those obtained from ground-based crystals. However, both the crystallographic R factor and the free R factor were slightly lower in the models derived from crystals produced in microgravity. The major difference between the two crystal growth systems is a lack of convection and sedimentation in a microgravity environment. This environment resulted in the growth of much larger, higher-quality crystals of the Sea Bence-Jones protein. Structurally, heretofore unrecognized grooves on the external surfaces of the Sea and other immunoglobulin-derived fragments are regular features and may offer supplementary binding regions for super antigens and other elongated ligands in the bloodstream and perivascular tissues.
Terzyan
Simon S
SS
Crystallography Program, Oklahoma Medical Research Foundation, 825 N.E. 13th Street, Oklahoma City, OK 73104, USA.
Bourne
Christina R
CR
Ramsland
Paul A
PA
Bourne
Philip C
PC
Edmundson
Allen B
AB
D001536:Bence Jones Protein / Q000737:chemistry* / Q000302:isolation & purification; D003460:Crystallization; D018360:Crystallography, X-Ray; D006801:Humans; D008958:Models, Molecular; D009101:Multiple Myeloma / Q000652:urine; D033363:Neutron Diffraction; D011487:Protein Conformation; D013026:Space Flight; D014867:Water / Q000737:chemistry; D014893:Weightlessness
D014867:Water; D001536:Bence Jones Protein