Derepression of a proline transport system in Staphylococcus aureus

Abstract

Staphylococcus aureus ATCC 6538P is auxotrophic tor proline. Under conditions of proline starvation, the organism synthesizes a transport system thus greatly increasing the rate of transport of proline into the cell. The proline transport systems of both the starved and unstarved cells were shown to be enzymatic, energy dependent, and specific for L-proline. Protein synthesis was required for derepression, and when the cells were fully induced, the organism established a non-exchangeable pool for proline, whose maintenance was dependent on protein synthesis. It is proposed that this transport system serves as a scavenging mechanism when the organism is in an environment deficient in proline.

Proline is biosynthesized from arginine in Staphylococcus aureus

“…Interestingly, in this connection, one of the characteristics of stationary phase bacteria, which can be regarded as bacteria starved for nutrients (Kolter et al ., 1993), is that glucose and amino acid transport systems are induced during starvation (Faquin & Oliver, 1984; Kolter et al ., 1993). Obbink & Campbell (1973) described increased proline transport in proline-starved S. aureus and Townsend & Wilkinson (1992) showed that strain 8325 Pro + had 3–5 times the activity of the high affinity proline transport system compared to strain 8325. Arginine and ornithine utilization is defective in B. suhtilis sigL mutants (Debarbouille et al ., 1991).…”