Abstract 2373 The Tesseract Quaternary Complex Model and Ca2+ Allostery in PTH1R

G protein-coupled receptor (GPCR) function has been modeled with its interactions with ligand and G proteins, with the Cubic Tertiary Complex Model (CTCM) representing the most complete, generic model with 8 receptor states. However, the model is limited to understanding plain ligand binding and doesn't consider allosteric modulators. To quantify and establish thermodynamic theory of allostery for GPCRs in general, we present the Tesseract Quaternary Complex Model (TQCM). An extension of the CTCM, the TQCM features a fourth dichotomous variable to the receptor states, presence of an allosteric modulator.