343 



Poln^eptklesandRelated Compounds 



Synthesis of the cell wall mucopeptides of staphjd^^o^^ 

 unaffected by chloramphenicol, but inhibited (at least indi- 

 rectly) by penicillin, bacitracin, cycloserine, novobiocin and 

 gentian violet. None of these inhibits protein synthesis 



Penicillin-inhibited Staphylococcus aureus accumulates three 

 closely related uridine nucleotides.- One of these has been as- 

 signed the structure : '■"'■ -'■ -^ 



\/N 



^N-Acetylmuramic Acid 



CH— CH.— CHo— COOH 



NH2 



I 

 NH CH, 



D-Ala D-Ala | I 



HOOC-CH-NH-C-CH-NH-C-CH-CH2-CH,-CH2 

 I II I II L-Lys 



CH3 O CH3 O 



This fragment may be the repeating unit of an activated cell 

 wall precursor, since the ratio of muramic acid: alanine glu- 

 tamic acid:lysine is 1 :3:1 :1, the same ratio found in lysozyme 

 digests of whole bacteria. In E. coli and Corynebacterium 

 diphthenae the lysine in the peptide chain is replaced by its 

 biosynthetic precursor, meso-diaminopimelic acid. 



^^ J. T. Park and N. J. Johnson, /. Biol. Chem. 179 585 (1949). 



J. T. Park and J. L. Strominger, Science 125 99 (1957). 

 2^ J. L. Strominger, /. Biol. Chem. 234 1520 (1959). 

 '-ndem.. Federation Proc. 18 334 (1959); Eijl Ito and Jack L. 

 Strommger, J. Biol. Chem. 235 PC5 (1960). 



