Determination of disulfide structure and N-glycosylation sites of the extracellular domain
The leptin receptor ( OB-R ) is a member of the class I cytokine receptor family and mediates the weight regulatory effects of its ligand through interaction with cytoplasmic kinases
The extracellular domain of this receptor is comprised of two immunoglobulin-like and cytokine- receptor homology domains each and type III fibronectin domains
The extracellular domain of human leptin receptor was expressed in and purified from Chinese hamster ovary cells and was found to contain extensive N-glycosylation (approximately 36% of the total protein )
The purified protein had a molecular weight of approximately 145,000 and exhibited ligand binding ability as evidenced by formation of ligand- receptor complex, followed by chemical cross-linking
The determined disulfide motif of the soluble leptin receptor contained several distinct cystine knots as well as 10 free cysteines
The N-glycosylation analysis revealed that Asn624 of the WSXWS motif ( residues 622-626 ) within the C-terminal cytokine receptor homology domain was glycosylated, indicating that this region is solvent-exposed
On the other hand, the N-terminal WSXWS motif was not glycosylated