1IGM

THREE DIMENSIONAL STRUCTURE OF AN FV FROM A HUMAN IGM IMMUNOGLOBULIN

1IGM の概要

• エントリーDOI: 10.2210/pdb1igm/pdb
• 分子名称: IGM-KAPPA POT FV (LIGHT CHAIN), IGM-KAPPA POT FV (HEAVY CHAIN) (3 entities in total)
• 機能のキーワード: immunoglobulin
• 由来する生物種: Homo sapiens (human); 詳細
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 26260.15

構造登録者

Fan, Z.-C.,Guddat, L.W.,Edmundson, A.B. (登録日: 1992-07-10, 公開日: 1993-10-31, 最終更新日: 2024-10-23)

主引用文献

Fan, Z.C.,Shan, L.,Guddat, L.W.,He, X.M.,Gray, W.R.,Raison, R.L.,Edmundson, A.B.
Three-dimensional structure of an Fv from a human IgM immunoglobulin.
J.Mol.Biol., 228:188-207, 1992

PubMed Abstract: An IgM(kappa) immunoglobulin from a patient (Pot) with Waldenstrom's macroglobulinemia was hydrolyzed with pepsin to release a fragment consisting of the 'variable' (V) domains of the light and heavy chains plus eight residue 'tails' from the 'constant' (C) domains. The crystal structure of this fragment was determined at 2.3 A resolution by molecular replacement and crystallographic refinement methods. When examined separately, the light chain component closely resembles another human kappa chain (Rei) in both the beta-pleated sheet regions and the 'hypervariable' loops. The conserved pleated sheets in the heavy chain are similar to those in the human Kol IgG1 protein, but the third hypervariable loop in particular is different from that in any immunoglobulin structure described to date. As in the Kol protein, this loop blocks the access to any internal active site along the light-heavy chain interface. Unlike the Kol protein, however, the loop does not protrude beyond the boundaries of a conventional antigen combining site. Instead, it forms a very compact structure, which fills almost all residual space between the domains. This is an example of one dominant complementarity-determining region (CDR) essentially negating the diversity possible with five other CDRs in the two chains. Ordered water molecules are associated with light chain constituents along the interface, but not with CDR3 of the heavy chain. In screening exercises the Pot IgM failed to bind a wide variety of peptides. Together, the results suggest that ligand binding can only occur on external surfaces of the protein. These surfaces carry a limited number of side chains usually assigned to CDRs in more typical antibodies.

PubMed: 1447781
DOI: 10.1016/0022-2836(92)90500-J

実験手法

X-RAY DIFFRACTION (2.3 Å)