Molecular characterization, modeling, in silico analysis of equine pituitary gonadotropin alpha subunit and docking interaction studies with ganirelix

Abstract

Equine pituitary gonadotropins (eLH, eFSH, eCG) are heterodimeric glycoprotein hormones with alpha (a) and beta (b) subunits. It is responsible for maintenance of pregnancy in mares during early gestation and fairly valuable for inducing superovulation in animals other than equines. The alpha subunit is common, while beta subunit is species-specific in all glycoprotein hormones. In the present investigation, molecular cloning and in silico characterization including homology modeling and molecular docking analysis of the equine chorionic gonadotropin (eCG) alpha subunit was carried out for gaining structural and functional insights into the eCG alpha subunit and its possible interaction with ganirelix, a gonadotropin-releasing hormone (GnRH) antagonist. The equine chorionic gonadotropin (eCG) alpha subunit expressed in pituitary gland was selected, amplified from total RNA, cloned and sequenced. The in silico analyses were made for homology modelling, structural details, epitope identification and chromosomal localization. Molecular docking studies of eCG alpha were undertaken with a drug ganirelix which is used to control ovulation and has antagonistic activity against GnRH. The protein sequence corresponding to selected open reading frame (ORF) was 99-100% similar with domesticated horse, Przewalski's horse, and 92-93% with Burchell's zebra and donkey. Molecular docking studies revealed the possible interaction of eCG alpha with ganirelix. The possible drug-macromolecule interactions were visualized between eCG alpha and ganirelix. The study will provide structural insight into unique sites and an alternate route of gonadotropin suppression applicable to assisted reproductive technologies.Keywords Equine Á Gonadotropin Á In silico Á Ganirelix Á Docking Anuradha Bhardwaj and Varij Nayan contributed equally to this work.Electronic supplementary material The online version of this article

Expression and characterization of recombinant single chain beta-alpha equine chorionic gonadotropin in prokaryotic host

“…In the present work, we carried out the expression, purification and characterization of single chain beta alpha eCG through bacterial expression system on similar lines of our earlier work on recombinant bovine inhibin alpha (Bhardwaj et al, 2012(Bhardwaj et al, , 2013. Recently, we reported the characterization and molecular docking analysis of eCG alpha molecule (Bhardwaj et al, 2017). We further aimed to clone and express pregnant mare serum gonadotropin (PMSG)/eCG/eLH in suitable host system.…”