Phylogenetic analysis of vertebrate β-2 adrenergic receptor sequences using maximum likelihood

G protein-coupled receptor (GPCRs) are most important classes of targets for small molecule drug discovery. Beta-2 adrenergic receptors (β2AR) was model system for this large and diverse family. β2Ars had been studied extensively to understand complex molecular changes which accompany receptor activation and signal transduction. The aim of this study is construct phylogenetic tree, identify conserved protein sequences which presented in the organism and interpret biological significance of result obtained. The sequences for vertebrate β2AR were obtained from National Centre for Biotechnology Information (NCBI) and saved in FASTA files. The sequences were aligned, trimmed and conserved protein sequences were determined by using ClustalX 2.1 and BioEdit. A phylogenetic tree was constructed using maximum likelihood method bootstrapped at 1000 replications by using MEGA version 6.06. The generated phylogenetic tree showed that higher vertebrate systems such as mammals especially primates can be used to related with humans and best serve as model for β-2 adrenergic pharmacology. Meanwhile, other organisms can be used in ascertaining pattern of molecular diversity across organisms. The aligned vertebrate β2AR sequences showed that important binding regions (TM3, TM5 and TM6) in ligand-receptor interaction are conserved. Therefore, experimental organism proved to have functional equivalent of possible drug targets. Besides, short conserved sequences are found to be associated with the protein’s conformation, indicated the structure of the protein is conserved across organism.