Stereospecificity of Tripeptide Utilization in a Methionine Auxotroph of Escherichia coli K-12
AUTOR(ES)
Becker, Jeffrey M.
RESUMO
The stereospecificity of peptide utilization in Escherichia coli K-12 4212, a methionine auxotroph, was investigated using diastereomers of trimethionine and trimethionine methyl ester. Of the eight stereoisomers examined, only l-Met-l-Met-l-Met, l-Met-l-Met-d-Met, and d-Met-l-Met-l-Met and the corresponding methyl esters serve as growth substrates. Triornithine-resistant mutants of strain 4212 were isolated which failed to transport d-Met-l-Met-l-Met. These results provide evidence that an oligopeptide containing a d residue at its amine terminus can enter E. coli by the oligopeptide transport system.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=245749Documentos Relacionados
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