TY - JOUR

T1 - Intersubunit bridge formation governs agonist efficacy at nicotinic acetylcholine alpha4beta2 receptors

T2 - Unique role of halogen bonding revealed

AU - Rohde, Line Aagot Hede

AU - Ahring, Philip Kiær

AU - Jensen, Marianne Lerbech

AU - Nielsen, Elsebet Østergaard

AU - Peters, Dan

AU - Helgstrand, Charlotte

AU - Krintel, Christian

AU - Harpsøe, Kasper

AU - Gajhede, Michael

AU - Kastrup, Jette Sandholm

AU - Balle, Thomas

N1 - Keywords: acetylcholine binding protein; lymnaea stagnalis; crystal structure; nicotinic acetylcholine receptor; agonist ; efficacy

PY - 2012/2/3

Y1 - 2012/2/3

N2 - The a4ß2 subtype of the nicotinic acetylcholine receptor (nAChR) has been pursued as a drug target for treatment of psychiatric and neurodegenerative disorders and smoking cessation aids for decades. Still, a thorough understanding of structure-function relationships of a4ß2 agonists is lacking. Using binding experiments, electrophysiology and X-ray crystallography we have investigated a consecutive series of five prototypical pyridine-containing agonists derived from 1-(pyridin-3-yl)-1,4-diazepane. A correlation between binding affinities at a4ß2 and the acetylcholine binding protein from Lymnaea stagnalis (Ls-AChBP) confirms Ls-AChBP as structural surrogate for a4ß2 receptors. Crystal structures of five agonists with efficacies at a4ß2 from 21-76% were determined in complex with Ls-AChBP. No variation in closure of loop C is observed despite large efficacy variations. Instead, the efficacy of a compound appears tightly coupled to its ability to form a strong inter-subunit bridge linking the primary and complementary binding interfaces. For the tested agonists, a specific halogen bond was observed to play a large role in establishing such strong inter-subunit anchoring.

AB - The a4ß2 subtype of the nicotinic acetylcholine receptor (nAChR) has been pursued as a drug target for treatment of psychiatric and neurodegenerative disorders and smoking cessation aids for decades. Still, a thorough understanding of structure-function relationships of a4ß2 agonists is lacking. Using binding experiments, electrophysiology and X-ray crystallography we have investigated a consecutive series of five prototypical pyridine-containing agonists derived from 1-(pyridin-3-yl)-1,4-diazepane. A correlation between binding affinities at a4ß2 and the acetylcholine binding protein from Lymnaea stagnalis (Ls-AChBP) confirms Ls-AChBP as structural surrogate for a4ß2 receptors. Crystal structures of five agonists with efficacies at a4ß2 from 21-76% were determined in complex with Ls-AChBP. No variation in closure of loop C is observed despite large efficacy variations. Instead, the efficacy of a compound appears tightly coupled to its ability to form a strong inter-subunit bridge linking the primary and complementary binding interfaces. For the tested agonists, a specific halogen bond was observed to play a large role in establishing such strong inter-subunit anchoring.

KW - Former Faculty of Pharmaceutical Sciences

U2 - 10.1074/jbc.M111.292243

DO - 10.1074/jbc.M111.292243

M3 - Journal article

C2 - 22170047

VL - 287

SP - 4248

EP - 4259

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

SN - 0021-9258

IS - 6

ER -