| Primary Identifier | IPR043698 | Type | Family |
| Short Name | Racemase_Bsr/Lyr |
| description | The short peptides that forms cross-links between glycan chains in the peptidoglycan polymer in bacterial cell walls require d-amino acids (DAA), being d-Alanine and d-Glutamate the most predominant ones. DAA are generated from the l-enantiomers by specific alanine and glutamate racemases. However, diverse bacteria can produce non-canonical DAA (NCDAA) components of the cell wall, that relies on periplasmic broad-spectrum racemases (Bsr) activity. Lysine racemase is another enzyme present in some organisms and catalyses the conversion of l-Lys to d-Lys but it also can use l-Arg as substrate. Together with Bsr they are classified as Group III racemases []. These NCDAA are involved in different cellular processes including biofilm stability, sporulation and cell communication and allow pathogenic bacteria to adapt in adverse environments []. Sequence studies revealed that Bsr and Lyr contained catalytic Lys and Tyr residues at equivalent positions to that in alanine racemases [, ]. Structural analyses between Bsr from Vibrio cholerae (BsrV) and more restricted enzymes revealed that it exhibits a wider entry site and channel which may facilitate interaction with amino-acid substrates larger than alanine. The catalytic site of BsrV-like racemases is more relaxed that those of related alanine racemases, which is probably due to differences on chamber components and to different interactions of the enzymatic domains to form them [, ]. Crystal structure of Lyr revealed a similar fold of alanine racemases containing an N-terminal α-β barrel and a C-terminal β-stranded domain []. |
