1EGG

STRUCTURE OF A C-TYPE CARBOHYDRATE-RECOGNITION DOMAIN (CRD-4) FROM THE MACROPHAGE MANNOSE RECEPTOR

Summary for 1EGG

• Entry DOI: 10.2210/pdb1egg/pdb
• Related: 1EGI
• Descriptor: MACROPHAGE MANNOSE RECEPTOR, CALCIUM ION (3 entities in total)
• Functional Keywords: c-type lectin, mannose receptor, sugar binding protein
• Biological source: Homo sapiens (human)
• Cellular location: Endosome membrane; Single-pass type I membrane protein: P22897
• Total number of polymer chains: 2
• Total formula weight: 33721.43

Authors

Feinberg, H.,Park-Snyder, S.,Kolatkar, A.R.,Heise, C.T.,Taylor, M.E.,Weis, W.I. (deposition date: 2000-02-15, release date: 2000-08-30, Last modification date: 2024-10-30)

Primary citation

Feinberg, H.,Park-Snyder, S.,Kolatkar, A.R.,Heise, C.T.,Taylor, M.E.,Weis, W.I.
Structure of a C-type carbohydrate recognition domain from the macrophage mannose receptor.
J.Biol.Chem., 275:21539-21548, 2000

PubMed Abstract: The mannose receptor of macrophages and liver endothelium mediates clearance of pathogenic organisms and potentially harmful glycoconjugates. The extracellular portion of the receptor includes eight C-type carbohydrate recognition domains (CRDs), of which one, CRD-4, shows detectable binding to monosaccharide ligands. We have determined the crystal structure of CRD-4. Although the basic C-type lectin fold is preserved, a loop extends away from the core of the domain to form a domain-swapped dimer in the crystal. Of the two Ca(2+) sites, only the principal site known to mediate carbohydrate binding in other C-type lectins is occupied. This site is altered in a way that makes sugar binding impossible in the mode observed in other C-type lectins. The structure is likely to represent an endosomal form of the domain formed when Ca(2+) is lost from the auxiliary calcium site. The structure suggests a mechanism for endosomal ligand release in which the auxiliary calcium site serves as a pH sensor. Acid pH-induced removal of this Ca(2+) results in conformational rearrangements of the receptor, rendering it unable to bind carbohydrate ligands.

PubMed: 10779515
DOI: 10.1074/jbc.M002366200

Experimental method

X-RAY DIFFRACTION (2.3 Å)