Skip to Content
Merck

Pseudoaeruginosins, nonribosomal peptides in Nodularia spumigena.

ACS chemical biology (2014-11-25)
Liwei Liu, Adnan Budnjo, Jouni Jokela, Bengt Erik Haug, David P Fewer, Matti Wahlsten, Leo Rouhiainen, Perttu Permi, Torgils Fossen, Kaarina Sivonen
ABSTRACT

Nodularia spumigena is a filamentous cyanobacterium that forms toxic blooms in brackish waters around the world through the production of the pentapeptide toxin nodularin. This cyanobacterium also produces large amounts of protease inhibitors belonging to the aeruginosin and spumigin families. Here we report the discovery of previously unknown protease inhibitors, pseudoaeruginosins NS1 (1) and NS2 (2), from 33 strains of N. spumigena isolated from the Baltic Sea. Pseudoaeruginosin NS1 (1) and NS2 (2) contain hexanoic acid, tyrosine, 4-methylproline, and argininal/argininol. The chemical structure of the two pseudoaeruginosins was verified by thorough comparison of the liquid chromatography-mass spectrometry (LC-MS) analyses of the extracts from the N. spumigena strains with synthetic peptides. The structures of the synthetic pseudoaeruginosins were confirmed using nuclear magnetic resonance spectroscopy. Surprisingly, the structure of pseudoaeruginosin NS1 (1) and NS2 (2) combines features of both aeruginosins and spumigins, suggesting that they have been produced through the joint action of both the spumigin and aeruginosin biosynthesis pathways. We screened with polymerase chain reaction and LC-MS 68 N. spumigena strains from the Baltic Sea and Australia. Pseudoaeruginosins were present in half of the Baltic Sea strains but were not found from the Australian strains. The production of pseudoaeruginosin seems to be coupled to the production of aeruginosins and 4-methylproline-containing spumigins. Pseudoaeruginosin NS1 was found to be as potent trypsin inhibitor as the most potent aeruginosins and spumigins with an IC50 of 0.19 ± 0.04 μM. This finding suggests that cooperation between the spumigin and aeruginosin biosynthetic pathways results in hybrid pseudoaeruginosin peptides.

MATERIALS
Product Number
Brand
Product Description

Supelco
Acetone, Pharmaceutical Secondary Standard; Certified Reference Material
Sigma-Aldrich
6-Maleimidohexanoic acid, 90% (GC)
Sigma-Aldrich
Sodium bicarbonate, BioXtra, 99.5-100.5%
Sigma-Aldrich
Sodium bicarbonate, powder, BioReagent, for molecular biology, suitable for cell culture, suitable for insect cell culture
Sigma-Aldrich
7-Amino-4-methylcoumarin, Chromophore for substrates
Supelco
Acetone, analytical standard
Sigma-Aldrich
Sodium bicarbonate, tested according to Ph. Eur.
Supelco
Calcium standard for AAS, analytical standard, 1.000 g/L Ca+2 in hydrochloric acid, traceable to BAM
Sigma-Aldrich
6-Maleimidohexanoic acid, ≥98.0% (HPLC)
Sigma-Aldrich
7-Amino-4-methylcoumarin, 99%
Sigma-Aldrich
Isopropyl alcohol, ≥99.7%, FCC, FG
Sigma-Aldrich
Acetone, suitable for HPLC, ≥99.9%
Sigma-Aldrich
Acetone, ≥99%, meets FCC analytical specifications
Sigma-Aldrich
Acetone, natural, ≥97%
USP
Sodium bicarbonate, United States Pharmacopeia (USP) Reference Standard
Sigma-Aldrich
Sodium bicarbonate, ReagentPlus®, ≥99.5%, powder
Sigma-Aldrich
Acetone, histological grade, ≥99.5%
Sigma-Aldrich
Acetone, ACS reagent, ≥99.5%
Sigma-Aldrich
Acetone, puriss. p.a., ACS reagent, reag. ISO, reag. Ph. Eur., ≥99.5% (GC)
Perindopril impurity A, European Pharmacopoeia (EP) Reference Standard
Supelco
Residual Solvent - Acetonitrile, Pharmaceutical Secondary Standard; Certified Reference Material
Sigma-Aldrich
Acetone, ACS reagent, ≥99.5%
Sigma-Aldrich
Sodium bicarbonate, ACS reagent, ≥99.7%
Sigma-Aldrich
Sodium bicarbonate, puriss., meets analytical specification of Ph. Eur., BP, USP, FCC, E500, 99.0-100.5%, powder
Sigma-Aldrich
Sodium bicarbonate, anhydrous, free-flowing, Redi-Dri, ReagentPlus®, ≥99.5%
Sigma-Aldrich
Acetone, Laboratory Reagent, ≥99.5%
Sigma-Aldrich
Acetone, puriss., meets analytical specification of Ph. Eur., BP, NF, ≥99% (GC)
Sigma-Aldrich
Sodium bicarbonate, anhydrous, free-flowing, Redi-Dri, ACS reagent, ≥99.7%
USP
Acetone, United States Pharmacopeia (USP) Reference Standard
Sigma-Aldrich
Sodium hydrogencarbonate, −40-+140 mesh, ≥95%