Conformational effects of Lys191 in the human GnRH receptor: mutagenesis and molecular dynamics simulations studies

Eduardo Jardón-Valadez; Arturo Aguilar-Rojas; Guadalupe Maya-Núñez; Alfredo Leaños-Miranda; Ángel Piñeiro; P Michael Conn; Alfredo Ulloa-Aguirre

doi:10.1677/JOE-08-0527

Made available online as an Accepted Preprint 26 February 2009
Accepted Preprint first posted online on 26 February 2009

Conformational effects of Lys191 in the human GnRH receptor: mutagenesis and molecular dynamics simulations studies

¹Research Unit in Reproductive Medicine, Hospital de Ginecobstetricia ‘Luis Castelazo Ayala’, Instituto Mexicano del Seguro Social, Apartado Postal 99-065, Unidad Independencia, Mexico D.F. CP 10101, Mexico²Departamento de Fisicoquímica, Facultad de Química, Universidad Nacional Autónoma de México, C.U., México D.F. CP04510, Mexico³Departamento de Física Aplicada, Facultad de Física, Universidad de Santiago de Compostela, E-15782 Santiago de Compostela, Spain⁴Oregon National Primate Research Center, Beaverton, 97006 Oregon, USA

(Correspondence should be addressed to A Ulloa-Aguirre; Email: aulloaa{at}servidor.unam.mx)

Abstract

In the present study, we analyzed the role of Lys191 on function, structure, and dynamic behavior of the human GnRH receptor (hGnRHR) and the formation of the Cys14–Cys200 bridge, which is essential for receptor trafficking to the plasma membrane. Several mutants were studied; mutants lacked either the Cys14–Cys200 bridge, Lys191 or both. The markedly reduced expression and function of a Cys14Ser mutant lacking the 14–200 bridge, was nearly restored to wild-type/ΔLys191 levels upon deletion of Lys191. Lys191 removal resulted in changes in the dynamic behavior of the mutants as disclosed by molecular dynamics simulations: the distance between the sulfur- (or oxygen-) sulfur groups of Cys (or Ser)14 and Cys200 was shorter and more constant, and the conformation of the NH₂-terminus and the exoloop 2 exhibited fewer fluctuations than when Lys191 was present. These data provide novel information on the role of Lys191 in defining an optimal configuration for the hGnRHR intracellular trafficking and function.