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Replacement of diaminopimelic acid by cystathionine or lanthionine in the peptidoglycan of Escherichia coli.
Mengin-Lecreulx, D; Blanot, D; van Heijenoort, J.
Afiliação
  • Mengin-Lecreulx D; Unité de Recherche Associée 1131 du Centre National de la Recherche Scientifique, Biochimie Moléculaire et Cellulaire, Université Paris-Sud, Orsay, France.
J Bacteriol ; 176(14): 4321-7, 1994 Jul.
Article em En | MEDLINE | ID: mdl-8021219
In Escherichia coli, auxotrophy for diaminopimelic acid (A2pm) can be suppressed by growth with exogenous cystathionine or lanthionine. The incorporation of cystathionine into peptidoglycan metabolism was examined with a dapA metC mutant, whereas for lanthionine, a dapA metA mutant strain was used. Analysis of peptidoglycan precursors and sacculi isolated from cells grown with epimeric cystathionine or lanthionine showed that meso-A2pm was totally replaced in the same position by either sulfur-containing amino acid. Moreover, mainly L-allo-cystathionine (95%) or meso-lanthionine (93%) was incorporated into the precursors and sacculi. For this purpose, a new, efficient high-pressure liquid chromatography (HPLC) technique for analysis of the cystathionine isomers was developed. The formation of the UDP-MurNAc tripeptide appeared to be a critical step, since the MurE synthetase accepted meso-lanthionine or D-allo- or L-allo-cystathionine in vitro as good substrates, although with higher Km values. Presumably, the 10-fold-higher UDP-MurNAc-L-Ala-D-Glu pool of cells grown with cystathionine or lanthionine ensured a normal rate of synthesis. The kinetic parameters of the MurF synthetase catalyzing the addition of D-alanyl-D-alanine were very similar for the meso-A2pm-,L-allo-cystathionine-, and meso-lanthionine-containing UDP-MurNAc tripeptides. HPLC analysis of the soluble fragments resulting from 95% digestion by Chalaropsis N-acetylmuramidase of the peptidoglycan material in isolated sacculi revealed that the proportion of the main dimer was far lower in cystathionine and lanthionine sacculi.
Assuntos

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Peptidoglicano / Cistationina / Ácido Diaminopimélico / Alanina / Escherichia coli Idioma: En Ano de publicação: 1994 Tipo de documento: Article

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Peptidoglicano / Cistationina / Ácido Diaminopimélico / Alanina / Escherichia coli Idioma: En Ano de publicação: 1994 Tipo de documento: Article