Annotation transfer by homology among closely related genomes helps to identify protein function in Plasmodium species

Abstract

Malaria is a major killer disease causing heavy loss in terms of life and medical expenditure. The genome of Plasmodium falciparum sequenced in 2002 but more than 60% of its meaning still remains unknown. We compared protein sequences from P. falciparum in the genomic sequences with P. vivax and P. knowlesi through standalone blast tool from NCBI. We found many proteins annotated in one species sharing high similarity with unannotated proteins in the other/s species. Based on the 'annotation transfer by homology' method we annotated 715 hypothetical proteins. By the latest information available as of 1st September our method annotated 343 protein sequences. Gene Ontology annotation with BLAST2GO revealed 128 proteins with Enzyme Codes among the 561 sequences mapped with GO terms. The kognitor results showed 542 proteins similar to proteins belonging to various KOG categories. More attention should be paid to these 'hypothetical' proteins as they can reveal unknown insights on the biology of organisms and have an impact in the field of drug discovery and medicine.