Biosynthetic arginine decarboxylase in Escherichia coli is synthesized as a precursor and located in the cell envelope

Abstract

The biosynthetic form of arginine decarboxylase (ADC) catalyzes the synthesis of agmatine, a precursor of putrescine, in Escherichia coli. Selective disruption of the cell envelope and an assessment of ADC activity or immunoprecipitable ADC in various fractions demonstrated its location between the cytoplasmic membrane and peptidoglycan layer. Expression in minicells of the speA gene encoding ADC resulted in the production of two immunoprecipitable species (74 and 70 kilodaltons). Studies in vivo with a pulse and chase of radiolabeled amino acid into the two species suggest a precursor-product relationship. This relationship was corroborated by demonstrating the accumulation of the 74-kilodalton species in a strain of E. coli unable to process signal sequences. Peptide mapping experiments with V8 protease, trypsin, and a-chymotrypsin demonstrated that the

Cadaverine induces closing of E. coli porins.

“…Cytosolic concentrations of putrescine have been reported to decrease when cells are grown in high osmolarity media (Munro et al, 1972). This efflux, as well as the periplasmic location of arginine decarboxylase responsible for putrescine synthesis (Buch and Boyle, 1985), might lead to high levels of putrescine in the periplasm. The presence of the polyamines in the vicinity of porin channels suggests that they may have an important role in vivo.…”

Retapamulin-assisted ribosome profiling reveals the alternative bacterial proteome

“…We examined the Ribo-RET-detected 5'-proximal iTIS of speA, the gene 375 that encodes arginine decarboxylase, an enzyme involved in polyamine production 376 (Michael, 2016). Arginine decarboxylase (SpeA) has been found in the E. coli 377 cytoplasmic and periplasmic fractions (Buch and Boyle, 1985) and was reported 378 to be represented by two polypeptide isoforms, SpeA-74, with an approximal 379 molecular weight of 74 kDa, and a smaller one of ~ 70 kDa, SpeA-70 (Buch and 380 Boyle, 1985;Wu and Morris, 1973). The latter protein was suggested to be a 381 product of co-secretional maturation of the full-length SpeA-74 (Buch and Boyle, 382 1985).…”

“…Initiation at the 5'-end proximal iTISs could produce alternative products with incomplete N-terminal signal sequences, Related to Figure 4 (A) Ribo-RET profile of the speA gene, showing peaks corresponding to pTIS (green flag) and iTIS (orange flag). The stop codon is indicated by a red stop sign.The putative signal sequence (indicated by dark blue letters) of SpeA-74(Buch and Boyle, 1985) is lacking in the alternative product SpeA-70 whose translation is initiated at the iTIS. The SpeA isoforms, whose translation is initiated at the pTIS or the iTIS are expected to have different cellular localization.…”

Sequestered end products and enzyme regulation: the case of ornithine decarboxylase.

“…First, in Escherichia coli, two pathways lead to putrescine formation (54). One is the ODC reaction; the other begins with decarboxylation of arginine by a periplasmic (8) enzyme, arginine decarboxylase. The product, agmatine, is taken into the cell and converted to putrescine by agamatine ureohydrolase, with the elimination of urea.…”