Putisolvin I-II

General info

Original publication	Kuiper, 2003
Original source	Pseudomonas putida PCL1445
Other known sources (non-putative)	Pseudomonas putida 267 (Kruijt, 2009) Pseudomonas putida E41 (Bernat, 2019)
Stereochemistry determined by	n.a.

Chemical properties

CAS	n.a.
Molecular formula	Putisolvin I: C65H113N13O19 Putisolvin II: C66H115N13O19
Molecular weight	Putisolvin I: 1380.7 g/mol Putisolvin II: 1394.7 g/mol
Mono-isotopic mass	Putisolvin I: 1379.8276 Da Putisolvin II: 1393.8432 Da
Solubility	n.a.
CMC	n.a.
Minimal surface tension	n.a.
3D conformation	n.a.
NMR data available in literature	n.a.

Introduction

Putisolvins were first described in the context of a study into the biosurfactant properties of bacteria grown on soils polluted with polycyclic aromatic hydrocarbons oil-contaminated soils. More specifically, it was observed that the original putisolvin-producing strain, Pseudomonas putida PCL1445, produces biosurfactant activity which was traced back to the production of two structurally related lipopeptides, putisolvin I and II.

Chemical structure

The structure of putisolvin I was initially determined by tandem mass spectrometry and ¹H NMR spectroscopy. The sequence determined by means of MS/MS was complemented by NMR sequential data obtained from ROESY spectra, , including those of the isobaric Leu/Ile residues. (Kuiper, 2003) A later study confirmed the structures of putisolvins I and II by the analysis of the NRPS systems responsible for the lipopeptide production. (Dubern, 2008) Analysis of the stereochemical make-up of putisolvin I and II has not (yet) been performed.

Putisolvins are cycling LPs which possess a hexanoic lipid tail, a peptide moiety of 12 amino acids whereby cyclization occurs between the side chain of Ser9 and the C-terminal carbonyl. The structure of putisolvin I is C6:0 – Leu – Glu – Leu – Ile – Gln – Ser – Val – Ile – Ser – Leu – Val – Ser. Putisolvin II has 14 Da more in mass due to the replacement of a valine to leucine/isoleucine on the 11th amino acid position.

Putisolvin II is isobaric to cocoyamide/gacamide, as both compounds have C₆₆H₁₁₅N₁₃O₁₉ as chemical formula. Hence, they cannot be discriminated based on mass spectrometry alone. Despite the identical chemical formula and molecular mass, both types of lipopeptides are structurally highly distinct, as they differ in amino acid sequence (both identity and length), size of the macrocycle and their fatty acid moiety.

Biological activity

For putisolvins produced by P. putida strain PCL1445, no antibacterial effects were observed against Pseudomonas fluorescens and Pseudomonas aeruginosa (Kuiper et al., 2004).

At higher concentrations (20–25 mg mL^-1), putisolvins immobilize zoospores from different oomycetes and cause lysis of entire zoospore populations within 1 min (Kruijt; tran, 2008)

Putisolvins produced by P. putida inhibited biofilm formation by P. aeruginosa PA14 and P. fluorescens WCS365 (Kuiper et al., 2004).

Genomic characterization

The biosynthesis genes responsible for putisolvin production in Pseudomonas putida PCL1445 are fully sequenced (Dubern, 2008)

References

Bernat, et al. “Characterization of extracellular biosurfactants expressed by a Pseudomonas putida strain isolated from the interior of healthy roots from Sida hermaphrodita grown in a heavy metal contaminated soil.” Current Microbiology76, 11 (2019): https://dx.doi.org/10.1007/s00284-019-01757-x.

Dubern, et al. “Genetic and functional characterization of the gene cluster directing the biosynthesis of putisolvin I and II in Pseudomonas putida strain PCL1445.” Microbiology (Reading)154, Pt 7 (2008): https://dx.doi.org/10.1099/mic.0.2008/016444-0.

Kruijt, et al. “Functional, genetic and chemical characterization of biosurfactants produced by plant growth-promoting Pseudomonas putida 267.” Journal of Applied Microbiology107, 2 (2009): https://dx.doi.org/10.1111/j.1365-2672.2009.04244.x.

Kuiper, et al. “Characterization of two Pseudomonas putida lipopeptide biosurfactants, putisolvin I and II, which inhibit biofilm formation and break down existing biofilms.” Molecular Microbiology51, 1 (2003): https://dx.doi.org/10.1046/j.1365-2958.2003.03751.x.