Comparative In-Silico Sequence and Structural Analysis of Catalase from Escherichia coli and Humans

Abstract

Hydrogen peroxide (H2O2) is a significant reactive oxygen species that can lead to cellular damage, particularly in eukaryotic organisms. Catalase, an enzyme, plays a crucial role in detoxifying H2O2 and sustaining cellular functions. Although substantial research has been conducted on catalase, limited comparative analyses examining the catalase sequences between Escherichia coli and humans, particularly in the context of active sites, exist. This study retrieved and analyzed the amino acid sequences and three-dimensional structures of catalase from both organisms using NCBI and PDB, alongside tools such as Clustal Omega, BLAST, MEGA, and PyMOL. The multiple sequence alignment identified 200 conserved, 122 physiochemically similar, and 163 variable amino acid residues, corresponding to an overall sequence identity of 45.17%. Phylogenetic analysis of a small representative dataset illustrated the evolutionary relationship between E. coli and human catalase. Structural superimposition of the active-site regions yielded a root mean square deviation (RMSD) of 0.295 Å, indicating close structural correspondence in this region despite the divergence in overall sequence and length. Essential functional residues, including active sites, domains, and motifs, were identified and compared. This computational analysis offers preliminary insights into the evolutionary and structural relationships of catalase between the two organisms, which may help direct future experimental work on oxidative-stress-related enzyme function.