Commercial uses of bioactive peptides require low cost, effective methods for their production. W... more Commercial uses of bioactive peptides require low cost, effective methods for their production. We developed a new carrier protein for high yield production of recombinant peptides in Escherichia coli very well suited for the production of toxic peptides like antimicrobial peptides. GKY20, a short antimicrobial peptide derived from the C-terminus of human thrombin, was fused to the C-terminus of Onconase, a small ribonuclease (104 amino acids), which efficiently drove the peptide into inclusion bodies with very high expression levels (about 200-250 mg/L). After purification of the fusion protein by immobilized metal ion affinity chromatography, peptide was obtained by chemical cleavage in diluted acetic acid of an acid labile Asp-Pro sequence with more than 95% efficiency. To improve peptide purification, Onconase was mutated to eliminate all acid labile sequences thus reducing the release of unwanted peptides during the acid cleavage. Mutations were chosen to preserve the differential solubility of Onconase as function of pH, which allows its selective precipitation at neutral pH after the cleavage. The improved carrier allowed the production of 15-18 mg of recombinant peptide per liter of culture with 96-98% purity without the need of further chromatographic steps after the acid cleavage. The antimicrobial activity of the recombinant peptide, with an additional proline at the N-terminus, was tested on Gram-negative and Gram-positive strains and was found to be identical to that measured for synthetic GKY20. This finding suggests that N-terminal proline residue does not change the antimicrobial properties of recombinant (P)GKY20. The improved carrier, which does not contain cysteine and methionine residues, Asp-Pro and Asn-Gly sequences, is well suited for the production of peptides using any of the most popular chemical cleavage methods.
We investigated the antimicrobial activity of PD-L4, a type 1 RIP from Phytolacca dioica. We foun... more We investigated the antimicrobial activity of PD-L4, a type 1 RIP from Phytolacca dioica. We found that this protein is active on different bacterial strains both in a native and denatured/alkylated form and that this biological activity is related to a cryptic peptide, named PDL440-65, identified by chemical fragmentation. This peptide showed the same antimicrobial activity of full-length protein and possessed, similarly to several antimicrobial peptides, an immunomodulatory effect on human cells. It assumes an alpha-helical conformation when interact with mimic membrane agents as TFE and likely bacterial membranes are a target of this peptide. To date PDL440-65 is the first antimicrobial peptide identified in a type 1 RIP.
Monocyclic phenols and catechols are important antioxidant compounds for the food and pharmaceuti... more Monocyclic phenols and catechols are important antioxidant compounds for the food and pharmaceutic industries; their production through biotransformation of low-added value starting compounds is of major biotechnological interest. The toluene o-xylene monooxygenase (ToMO) from Pseudomonas sp. OX1 is a bacterial multicomponent monooxygenase (BMM) that is able to hydroxylate a wide array of aromatic compounds and has already proven to be a versatile biochemical tool to produce mono- and dihydroxylated derivatives of aromatic compounds. The molecular determinants of its regioselectivity and substrate specificity have been thoroughly investigated, and a computational strategy has been developed which allows designing mutants able to hydroxylate non-natural substrates of this enzyme to obtain high-added value compounds of commercial interest. In this work, we have investigated the use of recombinant ToMO, expressed in cells of Escherichia coli strain JM109, for the biotransformation of n...
The structural modification of the resveratrol scaffold is currently an active issue in the quest... more The structural modification of the resveratrol scaffold is currently an active issue in the quest for more potent and versatile antioxidant derivatives for biomedical applications. Disclosed herein is an expedient and efficient entry to a novel class of resveratrol derivatives featuring an unprecedented 2-phenylbenzoselenophene skeleton. The new compounds were obtained in good yields by direct selenenylation of resveratrol with Se(0) and SO2Cl2 in dry THF. Varying the [Se : SO2Cl2 : resveratrol] ratio resulted in the formation of the parent benzoselenophene () and/or mono () and/or dichloro () benzoselenophene derivatives. All the benzoselenophene derivatives proved to be more efficient than resveratrol in the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing/antioxidant power (FRAP) assays, with showing an activity nearly comparable to that of Trolox. also proved to be more efficient inhibitors than the parent resveratrol in kinetic experiments of styrene autoxidation. DFT calculations of the O-H bond dissociation enthalpy (BDE) revealed that the introduction of the Se-atom causes a significant decrease of the BDE of 3-OH and 5-OH, with just a small increase of the 4'-OH BDE. Compounds showed no cytotoxicity at 5 μM concentrations on human keratinocyte (HaCaT) and intestinal (CaCo-2) cell lines.
Commercial uses of bioactive peptides require low cost, effective methods for their production. W... more Commercial uses of bioactive peptides require low cost, effective methods for their production. We developed a new carrier protein for high yield production of recombinant peptides in Escherichia coli very well suited for the production of toxic peptides like antimicrobial peptides. GKY20, a short antimicrobial peptide derived from the C-terminus of human thrombin, was fused to the C-terminus of Onconase, a small ribonuclease (104 amino acids), which efficiently drove the peptide into inclusion bodies with very high expression levels (about 200-250 mg/L). After purification of the fusion protein by immobilized metal ion affinity chromatography, peptide was obtained by chemical cleavage in diluted acetic acid of an acid labile Asp-Pro sequence with more than 95% efficiency. To improve peptide purification, Onconase was mutated to eliminate all acid labile sequences thus reducing the release of unwanted peptides during the acid cleavage. Mutations were chosen to preserve the differential solubility of Onconase as function of pH, which allows its selective precipitation at neutral pH after the cleavage. The improved carrier allowed the production of 15-18 mg of recombinant peptide per liter of culture with 96-98% purity without the need of further chromatographic steps after the acid cleavage. The antimicrobial activity of the recombinant peptide, with an additional proline at the N-terminus, was tested on Gram-negative and Gram-positive strains and was found to be identical to that measured for synthetic GKY20. This finding suggests that N-terminal proline residue does not change the antimicrobial properties of recombinant (P)GKY20. The improved carrier, which does not contain cysteine and methionine residues, Asp-Pro and Asn-Gly sequences, is well suited for the production of peptides using any of the most popular chemical cleavage methods.
We investigated the antimicrobial activity of PD-L4, a type 1 RIP from Phytolacca dioica. We foun... more We investigated the antimicrobial activity of PD-L4, a type 1 RIP from Phytolacca dioica. We found that this protein is active on different bacterial strains both in a native and denatured/alkylated form and that this biological activity is related to a cryptic peptide, named PDL440-65, identified by chemical fragmentation. This peptide showed the same antimicrobial activity of full-length protein and possessed, similarly to several antimicrobial peptides, an immunomodulatory effect on human cells. It assumes an alpha-helical conformation when interact with mimic membrane agents as TFE and likely bacterial membranes are a target of this peptide. To date PDL440-65 is the first antimicrobial peptide identified in a type 1 RIP.
Monocyclic phenols and catechols are important antioxidant compounds for the food and pharmaceuti... more Monocyclic phenols and catechols are important antioxidant compounds for the food and pharmaceutic industries; their production through biotransformation of low-added value starting compounds is of major biotechnological interest. The toluene o-xylene monooxygenase (ToMO) from Pseudomonas sp. OX1 is a bacterial multicomponent monooxygenase (BMM) that is able to hydroxylate a wide array of aromatic compounds and has already proven to be a versatile biochemical tool to produce mono- and dihydroxylated derivatives of aromatic compounds. The molecular determinants of its regioselectivity and substrate specificity have been thoroughly investigated, and a computational strategy has been developed which allows designing mutants able to hydroxylate non-natural substrates of this enzyme to obtain high-added value compounds of commercial interest. In this work, we have investigated the use of recombinant ToMO, expressed in cells of Escherichia coli strain JM109, for the biotransformation of n...
The structural modification of the resveratrol scaffold is currently an active issue in the quest... more The structural modification of the resveratrol scaffold is currently an active issue in the quest for more potent and versatile antioxidant derivatives for biomedical applications. Disclosed herein is an expedient and efficient entry to a novel class of resveratrol derivatives featuring an unprecedented 2-phenylbenzoselenophene skeleton. The new compounds were obtained in good yields by direct selenenylation of resveratrol with Se(0) and SO2Cl2 in dry THF. Varying the [Se : SO2Cl2 : resveratrol] ratio resulted in the formation of the parent benzoselenophene () and/or mono () and/or dichloro () benzoselenophene derivatives. All the benzoselenophene derivatives proved to be more efficient than resveratrol in the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing/antioxidant power (FRAP) assays, with showing an activity nearly comparable to that of Trolox. also proved to be more efficient inhibitors than the parent resveratrol in kinetic experiments of styrene autoxidation. DFT calculations of the O-H bond dissociation enthalpy (BDE) revealed that the introduction of the Se-atom causes a significant decrease of the BDE of 3-OH and 5-OH, with just a small increase of the 4'-OH BDE. Compounds showed no cytotoxicity at 5 μM concentrations on human keratinocyte (HaCaT) and intestinal (CaCo-2) cell lines.
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Papers by Elio Pizzo