%0 Journal
%T D-amino acids govern stationary phase cell wall remodeling in bacteria
%A Hubert Lam, Dong-Chan Oh, Felipe Cava, Constantin N. Takacs, Jon Clardy, Miguel A. de Pedro, Matthew K. Waldor
%J Science
%V 18
%P 1552-1555
%D 2009
%R https://doi.org/10.1126/science.1178123
%X In all known organisms, amino acids are predominantly thought to be synthesized and used as their L-enantiomers. Here, we found that bacteria produce diverse D-amino acids as well, which accumulate at millimolar concentrations in supernatants of stationary phase cultures. In Vibrio cholerae, a dedicated racemase produced D-Met and D-Leu, whereas Bacillus subtilis generated D-Tyr and D-Phe. These unusual D-amino acids appear to modulate synthesis of peptidoglycan, a strong and elastic polymer that serves as the stress-bearing component of the bacterial cell wall. D-Amino acids influenced peptidoglycan composition, amount, and strength, both by means of their incorporation into the polymer and by regulating enzymes that synthesize and modify it. Thus, synthesis of D-amino acids may be a common strategy for bacteria to adapt to changing environmental conditions.