IMGT/3Dstructure-DB: Querying the IMGT Database for 3D Structures in Immunology and Immunoinformatics (IG or Antibodies, TR, MH, RPI, and FPIA)

INTRODUCTION IMGT/3Dstructure-DB is the three-dimensional (3D) structure database of IMGT, the international ImMunoGenetics information system that is acknowledged as the global reference in immunogenetics and immunoinformatics. IMGT/3Dstructure-DB contains 3D structures of (1) antigen receptors that comprise immunoglobulins (IG) or antibodies and T cell receptors (TR), (2) major histocompatibility (MH) proteins of class I (MH1) and class II (MH2), (3) peptide/MH (pMH) complexes (pMH1, pMH2), (4) antigen receptor/antigen complexes (IG/Ag, TR/pMH), and (5) related proteins of the immune system (RPI) belonging to the immunoglobulin and MH superfamilies (IgSF and MhSF, respectively) and found in complexes with IG, TR, or MH. IMGT/3Dstructure-DB data are annotated according to the IMGT criteria, using IMGT/DomainGapAlign, and based on the IMGT-ONTOLOGY axioms and concepts. The use of IMGT/3Dstructure-DB is described here. It provides IMGT gene and allele identification (CLASSIFICATION), region and domain delimitations (DESCRIPTION), and amino acid (AA) positions according to the IMGT unique numbering (NUMEROTATION). IMGT/3Dstructure-DB provides the closest genes and alleles that are expressed in the AA sequences of the 3D structures, by aligning these sequences with the IMGT domain reference directory.