Preliminary crystallographic study of the Fab fragment of a monoclonal anti-phenylarsonate antibody

Preliminary crystallographic studies of the Fab fragment of an anti-azophenylarsonate antibody

Single crystals of the Fab fragment of a murine A/J anti-azophenylarsonate monoclonal antibody have been prepared by the vapor diffusion method. Antibody 3A7 uses the same combination of variable region gene segments (VK, JK, VH, JH) as do anti-azophenylarsonate antibodies bearing a predominant cross-reactive idiotype, but utilizes a different D gene segment. The crystals grow in the presence of beta-octylglucoside as tetragonal bipyramids in the space group of either P4(1)2(1)2 or P4(3)3(1)2 and with unit cell dimensions of a = b = 77.9 A, and c = 146.7 A. They diffract X-rays to better than 2.7 A resolution. Data up to 2.7 A resolution have been collected.

Three-dimensional structure of Fab R19.9, a monoclonal murine antibody specific for the p-azobenzenearsonate group

The crystal structure of Fab R19.9, derived from an anti-p-azobenzenearsonate monoclonal antibody, has been determined and refined to 2.8-A resolution by x-ray crystallographic techniques. Monoclonal antibody R19.9 (IgG2b kappa) shares some idiotopes with a major idiotype (CRIA) associated with A/J anti-p-azobenzenearsonate antibodies. The amino acid sequences of the variable (V) parts of the heavy (VH) and light (VL) polypeptide chains of monoclonal antibody R19.9 were determined through nucleotide sequencing of their mRNAs. The VL region is very similar to that of CRIA-positive anti-p-azobenzenearsonate antibodies as is VH, except for its third complementarity-determining region, which is three amino acids longer; it makes a loop, unique to R19.9, that protrudes into the solvent. A large number of tyrosine residues in the complementarity-determining region of VH and VL, with their side chains pointing towards the solvent, may have an important function in antigen binding.

Crystallization and preliminary crystallographic data for an antiprogesterone monoclonal antibody Fab' and steroid-Fab' complexes

Crystals of an Fab' from an antiprogesterone monoclonal antibody (IgG1) have been grown from 1.5 M-ammonium sulfate, pH 5.5 to 8.5. The single crystals are hexagonal rods, space group P6222 (or P6422), with cell dimensions a = b = 135.2 A, and c = 124.2 A. Cocrystals of the Fab' with progesterone, pregnanedione and other related steroids have been grown. The complex crystals have different morphology but are isomorphous with the native crystals. A hydroxy-progesterone derivative obtained by substituting an iodo-benzoyl group at the 11 alpha-hydroxyl position looks promising as a suitable heavy-atom candidate in addition to other potential conventional heavy-atom derivatives. All crystals diffract to at least 2.8 A resolution and are suitable for high-resolution X-ray diffraction studies.

Crystallization and preliminary crystallographic data of the Fab fragment of an anti-phenylalanine hydroxylase monoclonal antibody

Two crystal habits, one rod shaped and the other square prismatic, of the Fab fragment of a monoclonal anti-phenylalanine hydroxylase antibody have been grown using the method of vapour phase diffusion against polyethylene glycol 6000. The square prisms diffract to better than 2.8 A, belong to the space group P1 and have unit cell parameters a = 41.8 A, b = 50.3 A, c = 114.7 A, alpha = 97.6 degrees, beta = 91.7 degrees, gamma = 91.0 degrees, while the rod-shaped crystals belong to the space group P212121, have unit cell parameters a = 105.6 A, b = 119.8 A, c = 82.2 A and diffract to 3.5 A resolution.

X-ray diffraction studies of an anti-azophenylarsonate antibody and of an antigen-antibody complex

X-ray crystallographic studies of the Fab fragments of two murine monoclonal antibodies of predefined specificity are under way. Diffracted X-ray intensities of the crystalline native Fab fragment of an anti-azophenylarsonate antibody and of three heavy atom derivatives have been measured to a resolution of 3.5 A. A preliminary 6-A resolution electron density map has been obtained. The 6-A resolution structure of an antigen-antibody (hen lysozyme-Fab) complex has been determined. There are close contacts between the antigen and the antibody over a large contact area, about 20 X 25 A. At least two segments of the polypeptide chain of lysozyme, of about 10 amino acids each (positions 19-27 and 116-129), are involved in the contacts, as well as all six complementarity-determining regions of the antibody. No gross conformational changes are observed in the antigen at this resolution, although there are some smaller local changes in areas in contact with the antibody and elsewhere. The effects of amino acid substitutions on antigen recognition by the monoclonal anti-hen lysozyme antibody were investigated using different, closely related lysozymes. These effects can be readily explained in terms of the three-dimensional model presented here. A 3.5-A resolution electron density map has been calculated and is currently under study.

Preliminary crystallographic data for a monoclonal Fab fragment specific for HPr of the phosphoenolpyruvate: sugar phosphotransferase system of Escherichia coli

Crystals for Fab fragments from a monoclonal antibody to HPr of the phosphoenopyruvate:sugar phosphotransferase system of Escherichia coli have been obtained from 14% polyethylene glycol 6000, 5 mM-Tris X HCl, 50 mM-sodium phosphate and 0.2 M-sodium chloride at pH 8.0. The space group is P2(1) with a = 110.85 A, b = 66.18 A, c = 67.21 A, beta = 113.0 degrees and Z = 4. The crystals exhibit the forms [100], [011] and [011] and the solvent content is 47%.

Preliminary crystallographic study of the complex between the Fab fragment of a monoclonal anti-lysozyme antibody and its antigen

Preliminary crystallographic data are given for the complex between the Fab fragment of a monoclonal anti-lysozyme antibody and its antigen. This crystalline complex was found by screening a number of Fab-lysozyme complexes prepared from monoclonal anti-lysozyme antibodies produced by hybrids of BALB/c immune spleen cells with a non-secreting mouse hybrid myeloma line. The complex crystallizes in the monoclinic space group P21 with a = 55.5 (+/- 0.1) A, b = 143.5 (+/- 0.3) A, c = 49.1 (+/- 0.1) A, beta = 120 degrees 20' (+/- 10'). X-ray photographs show reflections extending to a resolution of 2.7 A. The crystals are suitable for high-resolution X-ray diffraction studies.

Preliminary crystallographic study of the Fc fragment of a monoclonal IgG2b murine immunoglobulin

The Fe fragment of a gamma 2b murine monoclonal anti-p-azophenylarsonate antibody (R19.9, IgG2b, kappa) has been crystallized. The crystals are tetragonal, space group P41 (or P43) with unit cell dimensions: a = b = 134.3 +/- 1.1 A, c = 144.0 +/- 0.7 A.