초록
<P><B>Abstract</B><P>Background<P><I>N</I>-acetylmuramyl-L-alanine amidases are cell wall modifying enzymes that cleave the amide bond between the sugar residues and stem peptide in peptidoglycan. Amidases play a vital role in septal cell wall cleavage and help separate daughter cells during cell division. Most amidases are zinc metalloenzymes, and <I>E. coli</I> cells lacking amidases grow as chains with daughter cells attached to each other. In this study, we have characterized two amidase enzymes from <I>Deinococcus indicus</I> DR1. <I>D. indicus</I> DR1 is known for its high arsenic tolerance and unique cell envelope. However, details of their cell wall biogenesis remain largely unexplored.</P></P><P>Results<P>We have characterized two amidases Ami1<I>Di</I> and Ami2<I>Di</I> from <I>D. indicus</I> DR1. Both Ami1<I>Di</I> and Ami2<I>Di</I> suppress cell separation defects in <I>E. coli</I> amidase mutants, suggesting that these enzymes are able to cleave septal cell wall. Ami1<I>Di</I> and Ami2<I>Di</I> proteins possess the Amidase_3 catalytic domain with conserved -GHGG- motif and Zn<SUP>2+</SUP> binding sites. Zn<SUP>2+</SUP>- binding in Ami1<I>Di</I> is crucial for amidase activity. AlphaFold2 structures of both Ami1<I>Di</I> and Ami2<I>Di</I> were predicted, and Ami1<I>Di</I> was a closer homolog to AmiA of <I>E. coli</I>.</P></P><P>Conclusion<P>Our results indicate that Ami1<I>Di</I> and Ami2<I>Di</I> enzymes can cleave peptidoglycan, and structural prediction studies revealed insights into the activity and regulation of these enzymes in <I>D. indicus</I> DR1.</P></P></P>