Comparison of the three‐dimensional structures of a human Bence‐Jones dimer crystallized on Earth and aboard US Space Shuttle Mission STS‐95

Abstract

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.

Formation of Amyloid Fibers by Monomeric Light Chain Variable Domains

“…In full-length LCs, V L s are connected to C L s through a joining (J) segment, which provides the domains with the flexibility to acquire conformations independent of each other. Such an architecture of the protein does not impose a particular orientation on V L s relative to connected C L s, as affirmed by the existence of several crystal structures (42,52,53). Therefore, a dimer of V L s maintains the ability to disassociate into amyloid-prone V L monomers, while still covalently attached to C L s. This flexibility explains why amyloid fibers of immunoglobulin can consist of fulllength LCs, just their V L s, or both.…”

Immunologic and structural analysis of eight novel domain-deletion β3integrin peptides designed for detection of HPA-1 antibodies

“…The substitution was made in the program XTALVIEW [27], and 500 cycles of energy minimization were conducted using the program CNS [28]. Molecular models of the CamTran007 antibody F(ab) light and heavy chains were made using the highly homologous chains from 1LHZ (chain A) [29] and 1AD9 (chain B) [30], respectively. The intact F(ab) was created by superimposing the light and heavy chains onto the F(ab) peptide from 1FSK, and then performing energy minimization of all side chain atoms in CNS.…”

Bence Jones KWR protein structures determined by X-ray crystallography

“…Among the latter were amino-acid residues A28 (Asp), A53 (Val), B53 (Val), A156 (Asp) and B214 (Thr). The first two residues belong to CDR loops 1 and 2 and were also found to be in disallowed regions in the other crystal forms, as well as in other -type light-chain dimers (Furey et al, 1983;Ely et al, 1989;Huang, Ainsworth, Stevens et al, 1996;Terzyan et al, 2003). Torsional strain is possibly the cause of these frequent outliers, since they are involved in tight -type (CDR-1) and -type (CDR-2) turns.…”

“…This angle may vary even among members of a single BJ population. A number of BJ protein structures have been determined using X-ray crystallography, each unique in sequence, antigen specificity, domain dispositions and other detailed features (Epp et al, 1975;Furey et al, 1983;Ely et al, 1989;Huang et al, 1994;Huang, Ainsworth, Solomon et al, 1996;Huang, Ainsworth, Stevens et al, 1996;Roussel et al, 1999;Terzyan et al, 2003).…”