PMID:355237

Citation	Miller, CG and Schwartz, G (1978) Peptidase-deficient mutants of Escherichia coli.J. Bacteriol. 135:603-11
Abstract	Mutant derivatives of Escherichia coli K-12 deficient in several peptidases have been obtained. Mutants lacking a naphthylamidase, peptidase N, were isolated by screening for colonies unable to hydrolyze L-alanine beta-naphthylamide. Other mutants were isolated using positive selections for resistance to valine peptides. Mutants lacking peptidase A, a broad-specificity aminopeptidase, were obtained by selection for resistance to L-valyl-L-leucine amide. Mutants lacking a dipeptidase, peptidase D, were isolated from a pepN pepA strain by selection for resistance to L-valyl-glycine. Starting with a pepN pepA pepD strain, selection for resistance to L-valyl-glycyl-glycine or several other valine peptides produced mutants deficient in another aminopeptidase, peptidase B. Mutants resistant to L-valyl-L-proline lack peptidase Q, an activity capable of rapid hydrolysis of X-proline dipeptides. Using these selection procedures, a strain (CM89) lacking five different peptidases has been isolated. Although still sensitive to valine, this strain is resistant to a variety of valine di- and tripeptides. The ability of this strain to use peptides as sources of amino acids is much more restricted than that of wild-type E. coli strains. Strains containing only one of the five peptidases missing in CM89 have been constructed by transduction. The peptide utilization profiles of these strains show that each of the five peptidases can function during growth in the catabolism of peptides.
Links	PubMed
Keywords	Alleles; Aminopeptidases; Escherichia coli; Genes; Mutation; Peptide Hydrolases; Peptides; Transduction, Genetic
edit table

Main Points of the Paper

Please summarize the main points of the paper.

Materials and Methods Used

Please list the materials and methods used in this paper (strains, plasmids, antibodies, etc).

Phenotype Annotations

See Help:AnnotationTable for details on how to edit this table.
<protect>

Phenotype of	Taxon Information	Genotype Information (if known)	Condition Information	OMP ID	OMP Term Name	ECO ID	ECO Term Name	Notes	Status
a mutation or genetic difference within a strain	Taxon: Escherichia coli Strain: K-12 Substrain: CM89 NCBI Taxon ID: 83333	Genotype of Reference Strain: pepQ Genotype of Experimental Strain : pepQ	Reference Condition:					Resistant to toxic, valine containing peptide
a mutation or genetic difference within a strain	Taxon: Escherichia coli Strain: K-12 Substrain: CM89 NCBI Taxon ID: 83333	Genotype of Reference Strain: pepN Genotype of Experimental Strain : pepN	Reference Condition:					Resistant to toxic, valine containing peptide
edit table

</protect>

References

See Help:References for how to manage references in omp dev.