Pseudomonas aeruginosa Alkaline Protease Can Facilitate Siderophore-Mediated Iron-Uptake via the Proteolytic Cleavage of Transferrins

• Published in: Biological & Pharmaceutical Bulletin 2006, Vol.29(11), pp.2295-2300
• Main Authors: Kim, Seong-Jung, Park, Ra-Young, Kang, Sang-Mi, Choi, Mi-Hwa, Kim, Choon-Mee, Shin, Sung-Heui
• Format: Article
• Language: English
• Subjects: alkaline protease; Anemia, Iron-Deficiency - metabolism; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Biological Transport; Cell Division; Culture Media, Conditioned - analysis; Culture Media, Conditioned - chemistry; Endopeptidases - genetics; Endopeptidases - metabolism; Humans; Hydrogen-Ion Concentration; iron; Iron - metabolism; Iron - pharmacokinetics; Peptide Hydrolases - genetics; Peptide Hydrolases - metabolism; Pseudomonas aeruginosa; Pseudomonas aeruginosa - enzymology; Pseudomonas aeruginosa - growth & development; Pseudomonas aeruginosa - metabolism; Pseudomonas Infections - metabolism; Pseudomonas Infections - microbiology; Reverse Transcriptase Polymerase Chain Reaction; RNA, Bacterial - genetics; RNA, Bacterial - metabolism; siderophore; Siderophores - biosynthesis; Time Factors; transferrin; Transferrin - metabolism
• ISSN: 0918-6158; 1347-5215
• DOI: 10.1248/bpb.29.2295

In order to determine whether Pseudomonas aeruginosa alkaline protease AprA is involved in facilitating siderophore-mediated iron-acquisition from human transferrins, we measured bacterial growth, the production of siderophore and AprA, iron-acquisition from transferrins, and the proteolytic cleavage of transferrins in an alkaline minimal medium (pH 8.3) containing human transferrins as an iron source and compared these on a time scale. The growth of P. aeruginosa was found to be stimulated in proportion to the iron-saturation levels of transferrins. AprA production and the proteolytic cleavage of transferrins began concomitantly with siderophore production from the early growth phase when P. aeruginosa was actively growing and consuming most iron for growth. However, the AprA-free, but siderophore-containing, culture ultrafiltrates could also remove iron from transferrin. These results indicate that alkaline protease AprA can facilitate the siderophore-mediated iron-uptake of P. aeruginosa via the proteolytic cleavage of transferrins. However, the proteolytic cleavage by AprA is not essentially required for iron-acquisition from transferrins.