THE HEXOKINASE 1 GENE OF BLOODSTREAM FORM Trypanosoma brucei brucei (FEDERE ISOLATE) CONSERVES AMINO ACIDS IN DOMAINS AND MOTIFS PECULIAR TO THE HEXOKINASE 2 SUPERFAMILY

Abstract

Trypanosoma brucei brucei hexokinase is the first key regulatory enzyme of the glycolytic pathway which serves as the only source of ATP and nucleic acid precursors for the parasite in the infective stage. This enzyme is attracting much interest because during the infective stage of the parasites, the bloodstream form (BSF) of this parasite depends solely on glycolysis because of its poorly developed mitochondrion. This research, therefore, attempted to characterize the hexokinase 1 gene of the T. b. brucei (Federe isolate) which is prevalent in Nigeria. The parasites were grown in rats and purified by diethyl aminoethyl (DEAE) cellulose chromatography. The genomic DNA was isolated, and the parasites hexokinase 1 gene amplified using consensus primers. The amplicon was purified and sequenced. The sequences were studied using software from the National Centre for Biotechnology Information (NCBI) and CLAWSTAL W server. The nucleotide sequence (Accession number MH198230) and the translated amino acids revealed high similarity with sequences of Trypanosoma brucei brucei TREU 927, T. brucei gambiense and Trypanosoma cruzi but low similarity with Human Glucokinase (hexokinase IV). The translated peptide sequence contains the N-terminal peroxisome-targeting signal (PTS-2) that is peculiar to glycosome containing organisms; ATP-binding and the hexokinase binding sites, and other amino acids in the domain peculiar to hexokinase 2 super-family were also conserved. These showed that T. brucei brucei hexokinase 1 conserves the unique features peculiar to the hexokinase 2 super-family and its uniquely from its mammalian forms make it a potential target for drug or vaccine against trypanosomiasis.