The stereoisomers of α∈-diaminopimelic acid. 2. Their distribution in the bacterial order Actinomycetales and in certain Eubacteriales

Abstract

The occurrence in various Eubacteriales of two of the three stereoisomers of oe-diaminopimelic acid (1:5 -diaminopentane -1:5 -dicarboxylic acid) has been reported in a preliminary survey (Hoare & Work, 1955a, b).The most common form was the meso isomer, but the LL isomer occurred in Clostridium perfringen8 (syn.Cl. welchii) and the two propionibacteria examined.In an earlier study of the Actinomycetales (carried out before reference isomers of diaminopimelic acid were available), the nocardia were found to resemble Mycobacterium tubercublo88 in their diaminopimelic acid content; streptomyces and an actinomyces contained what appeared, at the time, to be another amino acid differing slightly from diaminopimelic acid in its behaviour towards chromatography and enzymes (Work, 1953a, b; Work & Dewey, 1953a, b).This amino acid (then referred to as 'A') was isolated and tentatively identified as a higher homologue of diaminopimelic acid, but has now been shown to be u>-diaminopimelic acid.This paper describes the isolation and identification of LL-diaminopimelic acid from hydrolysed streptomyces and also the distribution of the three stereoisomers among representative members of the order Actinomycetales.In view ofthe finding of the less common LL isomer in certain propionibacteria and clostridia, further examinations are reported of the diaminopimelic acid isomer contents of related organisms.The following paper includes an examination of the distribution of two bacterial enzymes known to metabolize diaminopimelic acid, and compares the enzyme and diaminopimelic acid isomer contents of various organisms (Antia, Hoare & Work, 1957).A preliminary report has been given of these findings (Hoare & Work, 1956).MATERIALS AND METHODS Diaminopimelic acid.Reference isomers were prepared by enzymic resolution of synthetic diaminopimelic acid (Work, Birnbauxm, Winitz & Greenstein, 1955).The meso and LL isomers were also prepared by fractional crystallization of