| First Author | Olson LJ | Year | 1999 |
| Journal | J Biol Chem | Volume | 274 |
| Issue | 52 | Pages | 36905-11 |
| PubMed ID | 10601243 | Mgi Jnum | J:59066 |
| Mgi Id | MGI:1350860 | Doi | 10.1074/jbc.274.52.36905 |
| Citation | Olson LJ, et al. (1999) Mutational analysis of the binding site residues of the bovine cation-dependent mannose 6-phosphate receptor. J Biol Chem 274(52):36905-11 |
| abstractText | Mannose 6-phosphate receptors (MPRs) deliver soluble acid hydrolases to the lysosome in higher eukaryotic cells. The two MPRs, the cation-dependent MPR (CD-MPR) and the insulin-like growth factor II/cation-independent MPR, carry out this process by binding with high affinity to mannose 6-phosphate residues found on the N-linked oligosaccharides of their ligands. To elucidate the key amino acids involved in conveying this carbohydrate specificity, site-directed mutagenesis studies were conducted on the extracytoplasmic domain of the bovine CD-MPR. Single amino acid substitutions of the residues that form the binding pocket were generated, and the mutant constructs were expressed in transiently transfected COS-1 cells. Following metabolic labeling, mutant CD-MPRs were tested for their ability to bind pentamannosyl phosphate-containing affinity columns. Of the eight amino acids mutated, four (Gln-66, Arg-111, Glu-133, and Tyr-143) were found to be essential for ligand binding. In addition, mutation of the single histidine residue, His-105, within the binding site diminished the binding of the receptor to ligand, but did not eliminate the ability of the CD-MPR to release ligand under acidic conditions. |
