ChemInform Abstract: ANALYSIS OF THE ATOMIC ENVIRONMENT OF QUATERNARY AMMONIUM GROUPS IN CRYSTAL STRUCTURES, USING COMPUTERIZED DATA RETRIEVAL AND INTERACTIVE GRAPHICS: MODELING ACETYLCHOLINE-RECEPTOR INTERACTIONS

1983 ◽  
Vol 14 (1) ◽  
Author(s):  
R. E. JUN. ROSENFIELD ◽  
P. MURRAY-RUST
Keyword(s):  
Crystal Structures ◽  
Acetylcholine Receptor ◽  
Quaternary Ammonium ◽  
Data Retrieval ◽  
Interactive Graphics ◽  
Receptor Interactions

scholarly journals Structural studies of phosphorylation-dependent interactions between the V2R receptor and arrestin-2

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Qing-Tao He ◽  
Peng Xiao ◽  
Shen-Ming Huang ◽  
Ying-Li Jia ◽  
Zhong-Liang Zhu ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Conformational Changes ◽  
Nmr Spectrum ◽  
H Nmr ◽  
Interaction Sites ◽  
Receptor Interactions ◽  
Remote Sites ◽  
Genetic Code Expansion ◽  
G Protein Coupled ◽  
Interaction Change

AbstractArrestins recognize different receptor phosphorylation patterns and convert this information to selective arrestin functions to expand the functional diversity of the G protein-coupled receptor (GPCR) superfamilies. However, the principles governing arrestin-phospho-receptor interactions, as well as the contribution of each single phospho-interaction to selective arrestin structural and functional states, are undefined. Here, we determined the crystal structures of arrestin2 in complex with four different phosphopeptides derived from the vasopressin receptor-2 (V2R) C-tail. A comparison of these four crystal structures with previously solved Arrestin2 structures demonstrated that a single phospho-interaction change results in measurable conformational changes at remote sites in the complex. This conformational bias introduced by specific phosphorylation patterns was further inspected by FRET and 1H NMR spectrum analysis facilitated via genetic code expansion. Moreover, an interdependent phospho-binding mechanism of phospho-receptor-arrestin interactions between different phospho-interaction sites was unexpectedly revealed. Taken together, our results provide evidence showing that phospho-interaction changes at different arrestin sites can elicit changes in affinity and structural states at remote sites, which correlate with selective arrestin functions.

scholarly journals Crystal structures of three newN-halomethylated quaternary ammonium salts

2015 ◽  
Vol 71 (10) ◽  
pp. 1230-1235
Author(s):  
Carolina Múnera-Orozco ◽  
Rogelio Ocampo-Cardona ◽  
David L. Cedeño ◽  
Rubén A. Toscano ◽  
Luz Amalia Ríos-Vásquez
Keyword(s):  
Crystal Structures ◽  
Intermolecular Interactions ◽  
Quaternary Ammonium ◽  
Quaternary Ammonium Salts ◽  
Ammonium Salts ◽  
Compound I ◽  
Nlo Properties ◽  
Π Interactions

In the crystals of the titleN-halomethylated quaternary ammonium salts, C19H23IN+·I−, (I) [systematic name:N-(4,4-diphenylbut-3-en-1-yl)-N-iodomethyl-N,N-dimethylammonium iodide], C20H25IN+·I−, (II) [systematic name:N-(5,5-diphenylpent-4-en-1-yl)-N-iodomethyl-N,N-dimethylammonium iodide], and C21H27IN+·I−, (III) [systematic name:N-(6,6-diphenylhex-5-en-1-yl)-N-iodomethyl-N,N-dimethylammonium iodide], there are short I...I−interactions of 3.564 (4), 3.506 (1) and 3.557 (1) Å for compounds (I), (II) and (III), respectively. Compound (I) crystallizes in the Sohncke groupP21as an `enantiopure' compound and is therefore a potential material for NLO properties. In the crystal of compound (I), molecules are linked by C—H...I−and C—H...π interactions which, together with the I...I−interactions, lead to the formation of ribbons along [100]. In (II), there are only C—H...I−interactions which, together with the I...I−interactions, lead to the formation of helices along [010]. In (III), apart from the I...I−interactions, there are no significant intermolecular interactions present.

scholarly journals Chemical Modification of the Active Site of the Acetylcholine Receptor

1969 ◽  
Vol 54 (1) ◽  
pp. 245-264 ◽  
Author(s):  
Arthur Karlin
Keyword(s):  
Chemical Modification ◽  
Acetylcholine Receptor ◽  
Disulfide Bond ◽  
Active Site ◽  
Quaternary Ammonium ◽  
Competitive Inhibitor ◽  
Affinity Labels ◽  
Electrophorus Electricus ◽  
Depolarizing Agents ◽  
Monoquaternary Ammonium

The receptor for acetylcholine in the subsynaptic membrane of the electroplax of Electrophorus electricus is a protein with a disulfide bond in the vicinity of the active site. This disulfide can be reduced and reoxidized with concomitant inhibition and restoration of the response to acetylcholine and other monoquaternary ammonium-depolarizing agents. Conversely, the bisquaternary hexamethonium, normally a competitive inhibitor, causes depolarization, and the activity of decamethonium is increased following reduction of the disulfide. The reduced receptor can be alkylated by various maleimide derivatives and is then no longer reoxidizable. Some quaternary ammonium maleimide derivatives act as affinity labels of the reduced receptor, alkylating it at a rate three orders of magnitude faster then do uncharged maleimide derivatives. Other types of potential affinity labels also react only with the reduced receptor and the resulting covalently attached quaternary ammonium moieties interact with the active site, strongly activating the receptor. These results suggest a model for the active site and its transitions in which an activator such as acetylcholine bridges between a negative subsite and a hydrophobic subsite in the vicinity of the disulfide, causing an altered conformation around the negative subsite and a decrasee of a few angstroms in the distance between the two subsites.

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