53 research outputs found
The Cell Wall Peptidoglycan of Bacillus megaterium KM. I. Studies on the Stereochemistry of α,α'-Diaminopimelic Acid
α,α'-Diaminopimelic acid (DAP) occurs in the wall peptidoglycan of Bacillus megaterium KM predominantly in the form of its meso isomer (about 85% of the total residues) and, in minor amounts, in the form of its DD isomer. The amino groups on the L carbon of the meso-DAP residues are involved in peptide linkages to the glutamic acid residues. Most of the amino groups on the D carbon of the meso-DAP residues are free; some of them are substituted, thus probably serving to cross-link peptide subunits. These amino groups can be liberated by a Streptomyces endopeptidase. None of the DD-DAP residues have amino groups free. Moreover, these groups are not liberated by endopeptidase treatment. The peptidoglycan upon enzymatic degradation yields mainly two fractions. A major fraction is composed of disaccharide peptide monomer subunits containing only the meso isomer of DAP. A second minor fraction is composed of disaccharide peptide oligomers containing both meso and DD isomers of DAP. The meso-DAP residues isolated as monodinitrophenyl derivatives from both fractions have optical rotations and optical rotatory dispersions identical with that of synthetic monodinitrophenyl-meso-DAP obtained by dinitrophenylation of the amino group on the D carbon. The assignment of the DD configuration to the DAP residues which are not meso rests upon the optical rotatory properties of their bisdinitrophenyl derivatives
Transcription of a quail gene expressed in embryonic retinal cells is shut off sharply at hatching.
Localization of domains within the Drosophila Ref(2)P protein involved in the intracellular control of sigma rhabdovirus multiplication
Immunological cross-reactions and interactions between the Drosophila melanogaster ref(2)P protein and sigma rhabdovirus proteins
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