Background: Arginine deiminase of Mycoplasma hominis, an arginine catabolizing enzyme,
is currently in clinical trial for the treatment of arginine auxotrophic cancers. However, some
drawbacks such as instability and antigenicity have limited its application as a protein drug. Arginine
Deiminase (ADI) belongs to the guanidino-group modifying enzyme superfamily. Despite differences
in the primary amino acid sequences of various members of this superfamily, the folding and secondary
structures are conserved in all members. Despite structural similarities, ADIs in various species
have different levels of catalytic activity and physicochemical properties due to the differences in their
primary amino acid sequences. Therefore, investigating and comparing sequences between different
ADI producing bacterial strains could be helpful in the rational engineering of ADI.
Objective: In the current research, we used an in-silico approach to characterize and classify the available
reviewed protein sequences of ADI.
Results: 102 ADI sequences from SwissProt database were extracted. Subsequently, based on clustering
analyses, the sequence sets were divided into five distinct groups. Different physicochemical properties,
solubility, and antigenicity of the enzymes were determined. Some ADI sequences were introduced
as well-suited candidates for protein engineering; Lactobacillus fermentum ADI for low pI
value, Mycobacterium avium ADI for high aliphatic index, Bacillus licheniformis ADI for low GRAVY
index, Bradyrhizobium diazoefficiens ADI for low antigenicity and high stability index, and
among Mycoplasma ADIs, Mycoplasma arthritidis ADI for high stability and aliphatic index, and
Mycoplasma capricolum for low antigenicity.