Journal Article


C Hill
C G Gahan
R D Sleator



glutamate 5 kinase genetic complementation test phosphotransferases carboxyl group acceptor escherichia coli mutagenesis insertional molecular sequence data animals pathogenicity aldehyde oxidoreductases genetics mice inbred balb c glutamate 5 semialdehyde dehydrogenase listeria monocytogenes biosynthesis mice sequence analysis dna proline osmotic pressure

Identification and disruption of the proBA locus in Listeria monocytogenes: role of proline biosynthesis in salt tolerance and murine infection. (2001)

Abstract Intracellular accumulation of the amino acid proline has previously been linked to the salt tolerance and virulence potential of a number of bacteria. Taking advantage of the proBA mutant Escherichia coli CSH26, we identified a listerial proBA operon coding for enzymes functionally similar to the glutamyl kinase (GK) and glutamylphosphate reductase (GPR) enzyme complex which catalyzes the first and second steps of proline biosynthesis in E. coli. The first gene of the operon, proB, is predicted to encode GK, a 276-residue protein with a calculated molecular mass of 30.03 kDa and pl of 5.2. Distal to the promoter and overlapping the 3' end of proB by 17 bp is proA, which encodes GPR, a 415-residue protein with a calculated molecular mass of 45.50 kDa (pl 5.3). Using this information, we created a chromosomal deletion mutant by allelic exchange which is auxotrophic for proline. This mutant was used to assess the contribution of proline anabolism to osmotolerance and virulence. While inactivation of proBA had no significant effect on virulence in mouse assays (either perorally or intraperitoneally), growth at low (2 to 4% NaCl) and high (>6% NaCl) salt concentrations in complex media was significantly reduced in the absence of efficient proline synthesis. We conclude that while proline biosynthesis plays little, if any, role in the intracellular life cycle and infectious nature of Listeria monocytogenes, it can play an important role in survival in osmolyte-depleted environments of elevated osmolarity.
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Full list of authors on original publication

C Hill, C G Gahan, R D Sleator

Experts in our system

Colin Hill
University College Cork
Total Publications: 351
Cormac G M Gahan
University College Cork
Total Publications: 109
Roy D. Sleator
University College Cork
Total Publications: 44