 They have been described to synthesize more than 10 kinds of D-amino acids, most commonly D-alanine and D-glutamate for crosslinking within the peptidoglycan cell wall.
<clarity>  They have been described to synthesize more than 10 kinds of D-amino acids, most commonly D-alanine and D-glutamate for crosslinking within the peptidoglycan cell wall.
 They have been known to synthesize more than 10 kinds of D-amino acids, most commonly D-alanine and D-glutamate for crosslinking within the peptidoglycan cell wall.