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.
