The configuration of 2,6-diamino-3-hydroxypimelic acid in microbial cell walls.
beta-Hydroxydiaminopimelic acid, together with some diaminopimelic acid, occurs in the cell-wall mucopeptide of certain Actinomycetales. These components were converted into their di-DNP derivatives and separated by chromatography. Hence the relative proportions present in the cell walls of a number of species were measured. The problem of acid-induced inversion of configuration was studied. Of the diaminohydroxypimelic acids isomer B (see Scheme 2; amino groups meso, hydroxy group threo to its neighbouring amino group) always predominated but a small proportion of isomer D (amino groups l, hydroxy group erythro) also occurred. The configuration of the diaminohydroxypimelic acids was determined by periodate oxidation to glutamic gamma-semialdehyde, which underwent spontaneous ring-closure. Reduction with sodium borohydride produced optically active proline, the configuration of which was determined by direct measurement of the optical rotation of DNP-proline. Un-cross-linked diaminohydroxypimelic acid in the cell wall was oxidized with periodate in the presence of ammonia. Since the remaining amino group was bound in peptide linkage, ring-closure was prevented and borohydride reduction of the aldehyde-ammonia presumed to be present resulted in the formation of ornithine. The quantity of ornithine was used as a measure of the degree of cross-linking.
D000192:Actinomycetales / Q000032:analysis*; D001896:Boron Compounds; D002473:Cell Wall / Q000032:analysis*; D002854:Chromatography, Paper; D009905:Optical Rotatory Dispersion; D009952:Ornithine; D010084:Oxidation-Reduction; D010504:Periodic Acid; D010867:Pimelic Acids / Q000032:analysis*; D011392:Proline; D013237:Stereoisomerism
D001896:Boron Compounds; D010867:Pimelic Acids; D010504:Periodic Acid; D011392:Proline; D009952:Ornithine