The Preliminary Study About MGluR2 Allosteric Modulator's Binding Sites And Dimerization Mechanism

The neurotransmitter glutamate is an important neurotransmitter in the central nervous system, and related to a variety of mental and neurological degeneration disease such as Parkinson's disease, schizophrenia, depressed disease and other diseases. Normally, Glutamate Receptors include metabolic glutamic acid receptor(Metabotropic Glutamate Receptors) and ionic glutamate Receptors. Metabotropic glutamate Receptors belong to the C family of G Protein couple-receptor, participating in the neural signal transmission, a variety of physiological processes such as learning and memory. The same with G protein couple- receptors, m Glu Rs have a total of seven Transmembrane helical structure Domain(Heptahelical Transmembrane Domain, HD) and different lengths of film in the C- tail(C end tail), and the complex structure of Extracellular Domain(Extracellular Domain, ECD). m Glu Rs' s ECD structure Domain consists of two parts, the combination of ligand flytrap structure Domain(Venus Fly Trap, VFT) and the connection between the VFT and HD Cysteine enrichment structure Domain(Cysteine Rich Domain, CRD).The negative allosteric modulator of m Glu Rs can inhibit agonist of receptor activation intensity(Vmax), or influence receptor agonist's affinity(EC50) which regulates the activity of receptors. Research suggested that negative allosteric modulator general combination in the domain of seven transmembrane receptor structure(HD). But in view of the two common m Glu R2 negative allosteric modulator MNI137 and RO645229 specific combination in which structure of m Glu R2 domain, there is no literature reported. This research reference of previous literature reports of research methods of m Glu Rs' new negative allosteric modulator, combined with the bioinformatics analysis, selected 20 sites between TM2- TM7 and mutated amino acids into alanine, in turn do MNI137 / RO645229 on inhibition curve of Glutamate, through the analysis differences of the IC50 between mutations and wild-type receptor and the inhibition rate of the negative allosteric modulator, found MNI137 and RO645229 combining several key sites, combined with the molecular characteristics of the drug, a preliminary estimate about the conformational change before and after the receptor‘s negative allosteric modulator.In the human body, C GPCRs receptors are normally constitutively dimerizated, the family generally considered in the study of early m Glu Rs only forming a homodimers. But in 2011, reported in the literature, through the FRET methods, specific subtribe m Glu Rs can also occur in vitro between different source polymerization and form has the function of the two different source dimers, II m Glu Rs and III m Glu Rs have many FRET effect and can form different source dimers, but did not detect FRET effect between II m Glu Rs and I m Glu Rs.We overexpressed m Glu R2 in HEK293 cells, preliminary findings m Glu R2 and m Glu R5/1 can form a functional heterodimers, and in the formation of the heterodimers, receptor has a one-way selection mechanism, namely only selectively activated by m Glu R5/1 and cannot be activated by m Glu R2. And we found the Val860(846) of m Glu R1/5 sites has an important influence on interaction of m Glu R2 and m Glu R5/1.In conclusion, this research found pharmacological properties of m Glu R2 negative allosteric modulator MNI137 and RO645229, helpful for the analytical study of the structure of the transmembrane domain of m Glu R2, while the study about amino acids characteristic of m Glu R1 / 5 C-terminal will help analytical studies of m Glu R1/5 structure and function.