1IAM: Structure Of The Two Amino-Terminal Domains Of Human Intercellular Adhesion Molecule-1, Icam-1

The normal function of human intercellular adhesion molecule-1 (ICAM-1) is to provide adhesion between endothelial cells and leukocytes after injury or stress. ICAM-1 binds to leukocyte function-associated antigen (LFA-1) or macrophage-1 antigen (Mac-1). However, ICAM-1 is also used as a receptor by the major group of human rhinoviruses and is a catalyst for the subsequent viral uncoating during cell entry. The three-dimensional atomic structure of the two amino-terminal domains (D1 and D2) of ICAM-1 has been determined to 2.2-A resolution and fitted into a cryoelectron microscopy reconstruction of a rhinovirus-ICAM-1 complex. Rhinovirus attachment is confined to the BC, CD, DE, and FG loops of the amino-terminal Ig-like domain (D1) at the end distal to the cellular membrane. The loops are considerably different in structure to those of human ICAM-2 or murine ICAM-1, which do not bind rhinoviruses. There are extensive charge interactions between ICAM-1 and human rhinoviruses, which are mostly conserved in both major and minor receptor groups of rhinoviruses. The interaction of ICAMs with LFA-1 is known to be mediated by a divalent cation bound to the insertion (I)-domain on the alpha chain of LFA-1 and the carboxyl group of a conserved glutamic acid residue on ICAMs. Domain D1 has been docked with the known structure of the I-domain. The resultant model is consistent with mutational data and provides a structural framework for the adhesion between these molecules.
PDB ID: 1IAMDownload
MMDB ID: 56405
PDB Deposition Date: 1998/2/22
Updated in MMDB: 2011/11
Experimental Method:
x-ray diffraction
Resolution: 2.1  Å
Source Organism:
Similar Structures:
Biological Unit for 1IAM: dimeric; determined by author
Molecular Components in 1IAM
Label Count Molecule
Proteins (2 molecules)
Intercellular Adhesion Molecule-1(Gene symbol: ICAM1)
Molecule annotation
Chemicals (2 molecules)
* Click molecule labels to explore molecular sequence information.

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