IN SILICO STRUCTURE PREDICTION OF GLOSSINA MORSITANS MORSITANS ODORANT BINDING PROTEINS

Abstract

Glossina morsitans morsitans is the primary vector for trypanosome parasite which is causative agent for sleeping sickness in human and nagana in animals, conditions that are prevalence in sub Saharan Africa. In this study functional annotation and structure prediction of G. M. morsitans odorant binding proteins was done by BLAST searches against NCBI and PDB databases respectively. Multiple sequence alignment was performed by clustalW while genetic relatedness of G. m. morsitans with mosquitoes (Anopheles gambiae, Aedes aegypti and Culex quinquefasciatus) and fruit fly (Drosophila melanogaster) was determined based on PHYML. The 3D-structure prediction was determined and viewed using Swiss model and Swiss-Pdb Viewer program respectively. The GmmOBP9 had the highest percentage identity of 77.9% and e-value of 1.42e-10 with DroOBP83b as its ortholog. GmmOBP10 recorded the highest percentage identity among the mosquitoes studied having 60.23%, 57.65% and 62.35% for Anopheles, Aedes and Culex respectively. The lowest percentage identity of 27.4% and e-value of 0.04 was recorded for DroOBP56i by GmmOBP17 while GmmOBP3 recorded the lowest percentage identity among the mosquitoes (Anopheles and Aedes) with 19.50% and 24.06% respectively. The Gmm-OBPs had amino acid sequence length ranging from 88 to 240 with GmmOBP7 being the longest (240 aa with MW of 28.3kda and pI 5.78). GmmOBP20 had the lowest MW of 10.3 kda. The GmmOBPs had a theoretical pI range of 4.41 to 9.30. Multiple sequence alignment revealed the six conserved cysteine while phylogenetic studies indicate that GmmOBPs are closely related to Drosophila OBPs. Structural prediction of the GmmOBPs showed presence of between four to six helices with multiple alignments with respective templates confirming the location of the conserved six cysteines. This study predicts the three dimensional structure of G. m. morsitans OBPs and open avenues for functional studies as they form potential targets for control of tsetse vectors.