Interactions between the human sweet-sensing T1R2-T1R3 receptor and sweeteners detected by saturation transfer difference NMR spectroscopy.
The sweet receptor is a member of the G-protein coupled receptor family C that detects a wide variety of chemically and structurally diverse sweet-tasting molecules. We recently used saturation transfer difference spectroscopy (STD) to monitor the direct binding of a set of sweet agonists and antagonists to the human taste receptor in membranes prepared from human embryonic kidney (HEK293) cells transfected with and expressing the sweet receptor [F.M. Assadi-Porter, M. Tonelli, E. Maillet, K. Hallenga, O. Benard, M. Max, J.L. Markley, J. Am. Chem. Soc. 130 (2008) 7212-7213]. Here we review this work and related studies, discuss the procedures involved, and expand on their potential for identifying specific binding interactions of ligands to the membrane spanning and extracellular regions of the full heterodimeric sweet taste receptor. Whereas activity assays are unable to distinguish mutations that alter ligand-binding sites from those that alter signal transduction downstream of the binding site, STD NMR now allows us to make this distinction.
Assadi-Porter
Fariba M
FM
Biochemistry Department and National Magnetic Resonance Facility at Madison, 433 Babcock Drive, Madison WI 53706, USA. fariba@nmrfam.wisc.edu
Tonelli
Marco
M
Maillet
Emeline L
EL
Markley
John L
JL
Max
Marianna
M
D000818:Animals; D001665:Binding Sites / Q000502:physiology; D002460:Cell Line; D006801:Humans; D008024:Ligands; D051379:Mice; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding / Q000502:physiology; D043562:Receptors, G-Protein-Coupled / Q000819:agonists / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D013549:Sweetening Agents / Q000737:chemistry* / Q000378:metabolism
D008024:Ligands; D010940:Plant Proteins; D043562:Receptors, G-Protein-Coupled; D013549:Sweetening Agents; C090521:brazzein protein, Pentadiplandra brazzeana; C431926:taste receptors, type 1