1DBA

THREE-DIMENSIONAL STRUCTURE OF AN ANTI-STEROID FAB' AND PROGESTERONE-FAB' COMPLEX

1DBA の概要

• エントリーDOI: 10.2210/pdb1dba/pdb
• 分子名称: IGG1-KAPPA DB3 FAB (LIGHT CHAIN), IGG1-KAPPA DB3 FAB (HEAVY CHAIN), ETHANOL (3 entities in total)
• 機能のキーワード: immunoglobulin
• 由来する生物種: Mus musculus (house mouse); 詳細
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 47727.38

構造登録者

Arevalo, J.H.,Wilson, I.A. (登録日: 1992-11-10, 公開日: 1993-10-31, 最終更新日: 2024-11-13)

主引用文献

Arevalo, J.H.,Stura, E.A.,Taussig, M.J.,Wilson, I.A.
Three-dimensional structure of an anti-steroid Fab' and progesterone-Fab' complex.
J.Mol.Biol., 231:103-118, 1993

PubMed Abstract: The monoclonal anti-progesterone antibody DB3 binds progesterone with nanomolar affinity (Ka approximately 10(9) M-1), suggesting high specificity. However, DB3 also cross-reacts with similar affinity with a subgroup of structurally distinct, progesterone-like steroids. Crystals of the unliganded Fab' and various steroid-Fab' complexes are isomorphous and belong to the hexagonal space group, P6(4)22, with unit cell dimensions of a = b = 135 A, c = 124 A. Structures of free and progesterone-bound Fab' have been determined by X-ray crystallography at 2.7 A resolution using molecular replacement techniques. Progesterone is bound in a hydrophobic pocket formed mainly by the interaction of three complementarity determining regions L1, H2 and H3. The orientation of the ligand in the binding site was aided by both crystallographic and biochemical analyses of substituted steroids. The indole side-chain of TrpH100 of the DB3 has two different conformations, inter-converting "open" and "closed" forms of the antibody combining site. The TrpH100 indole thus appears to be acting as an antibody-derived surrogate ligand for its own hydrophobic binding pocket. These structures provide the first atomic view of how a steroid interacts with a protein and offer a structural explanation for the restriction of the anti-progesterone response to the VGAM3.8 family of VH genes.

PubMed: 8496956
DOI: 10.1006/jmbi.1993.1260

実験手法

X-RAY DIFFRACTION (2.8 Å)