Two recombinant peptides, SpStrongylocins 1 and 2, from Strongylocentrotus purpuratus, show antimicrobial activity against Gram-positive and Gram-negative bacteria.
The cysteine-rich strongylocins were the first antimicrobial peptides (AMPs) discovered from the sea urchin species, Strongylocentrotus droebachiensis. Homologous putative proteins (called SpStrongylocin) were found in the sister species, S. purpuratus. To demonstrate that they exhibit the same antibacterial activity as strongylocins, cDNAs encoding the 'mature' peptides (SpStrongylocins 1 and 2) were cloned into a direct expression system fusing a protease cleavage site and two purification tags to the recombinant peptide. Both recombinant fusion peptides were expressed in a soluble form in an Escherichia coli strain tolerant to toxic proteins. Enterokinase was used to remove the fusion tags and purified recombinant SpStrongylocins 1 and 2 showed antimicrobial activity against both Gram-negative and Gram-positive bacteria. The results of membrane integrity assays against cytoplasmic membranes of E. coli suggest that both recombinant SpStrongylocins 1 and 2 conduct their antibacterial activity by intracellular killing mechanisms because no increase in membrane permeability was detected.
Li
Chun
C
Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics, University of Tromsø, Breivika, N-9037 Tromsø, Norway.
Blencke
Hans-Matti
HM
Smith
L Courtney
LC
Karp
Matti T
MT
Stensvåg
Klara
K
D000595:Amino Acid Sequence; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology*; D001483:Base Sequence; D004591:Electrophoresis, Polyacrylamide Gel; D006090:Gram-Negative Bacteria / Q000187:drug effects*; D006094:Gram-Positive Bacteria / Q000187:drug effects*; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D047270:Strongylocentrotus purpuratus / Q000502:physiology*
D023181:Antimicrobial Cationic Peptides; D011994:Recombinant Proteins