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Lactophoricin [id=LAP0001]

Synonym: PP3 f(113-135) ; Lactophoricin N-23-T

Producer Organism : Native Protein : Production Method :
Cow PP3 Synthetic
Activity : Antibacterial
Target Organisms :

Gram-positive: Streptococcus thermophilus NG40Z (MIC=10 然), Streptococcus thermophilus AFI08 (IC50=1.7 然), Staphylococcus aureus ATCC 25923 (IC50=45 然), Listeria innocua MC 2 (IC50=75 然).

Gram-negative: Salmonella St Paul DSV 29 (IC50=40 然), Pseudomonas aeruginosa ATCC 27853 (IC50=110 然).

NOTE: No activity against Escherichia coli ATCC 25922 (>350 然), Escherichia coli USEC08, Staphylococcus aureus USSA08 (>80 然) .

Description :
Production method: Synthetic.

LAP0001 and LAP0003 peptides both interact with phospholipids, but only LAP0001 can incorporate into planar lipidic bilayers by forming voltage-dependent channels. The conductance levels indicate that channel formation may be achieved by association of 4 to 6 bundles of peptides according to the barrelstave model. Although lactophoricin displayed a low antibacterial activity compared with other peptides, this is the first report of an antimicrobial peptide from bovine milk PP3 or, in more general terms, from the PP3 protein family (Citation 1).
Length : 23 Mass (Da): 2 683.28 Common Amino Acids : K
Isolectric Point : 10.03 Net Charge : 3 Absent Amino Acids : CDGMPQRW
Basic Residues : 5 Acidic Residues : 2 Hydrophobic Residues : 9
Polar Residues : 7 Boman Index : -27.12 Hydropathy Index : -0.096
Aliphatic Index : 93.04 Instability Index : 0 Extinction Coefficient : 1490
Absorbance 280nm : 67.73

Wheel representation

Hydrophobicity plot

Red solid plot : values according to the hydrophobicity scale of Kyte and Doolittle (reference paper).
Yellow dashed plot : Experimentally determined hydrophobicity scale for proteins at membrane interfaces(reference paper).
Green dotted-dashed plot : prediction of transmembrane helices (reference paper). In this scale (unlike the others), more negative values reflect greater hydrophobicity.

Citation: 1

Antibacterial activity of lactophoricin, a synthetic 23-residues peptide derived from the sequence of bovine milk component-3 of proteose peptone

Cited Entries: LAP0001, LAP0003

Authors:Campagna, S., Mathot, A.G., Fleury, Y., Girardet, J.M., Gaillard, J.L.
Journal: Journal of Dairy Science 2004, 87(6).
CrossRef External Link
Abstract: A synthetic peptide of 23 residues corresponding to the carboxyterminal 113 to 135 region of component-3 of proteose peptone (PP3) has been investigated with regard to its antibacterial properties. This cationic amphipathic peptide that we refer to as lactophoricin, displayed a growth-inhibitory activity against both gram-positive and gram-negative bacteria. For most of the strains tested, bacterial growth was observed in the presence of lactophoricin except for Streptococcus thermophilus. In that case, lactophoricin exhibited a minimum inhibitory concentration of 10 μM and a minimum lethal concentration of 20 μM. No hemolysis of human red blood cells was detected for peptide concentrations between 2 to 200 μM, indicating that lactophoricin would be noncytotoxic when used in this concentration range.
Keywords: bovine milk; component-3 of proteose peptone; antimicrobial activity; amphipathic peptide
Citation: 2

Solution and solid-state NMR structural studies of antimicrobial peptides LPcin-I and LPcin-II

Cited Entries: LAP0001, LAP0003

Authors:Park, T.-J., Kim, J.-S., Ahn, H.-C., Kim, Y.
Journal: Biophysical Journal 2011, 101(5): 9.
Abstract: Lactophoricin (LPcin-I) is an antimicrobial, amphiphatic, cationic peptide with 23-amino acid residues isolated from bovine milk. Its analogous peptide, LPcin-II, lacks six N-terminal amino acids compared to LPcin-I. Interestingly, LPcin-II does not display any antimicrobial activity, whereas LPcin-I inhibits the growth of both Gram-negative and Gram-positive bacteria without exhibiting any hemolytic activity. Uniformly 15N-labeled LPcin peptides were prepared by the recombinant expression of fusion proteins in Escherichia coli, and their properties were characterized by electrospray ionization mass spectrometry, circular dichroism spectroscopy, and antimicrobial activity tests. To understand the structure-activity relationship of these two peptides, they were studied in model membrane environments by a combination of solution and solid-state NMR spectroscopy. We determined the tertiary structure of LPcin-I and LPcin-II in the presence of dodecylphosphorylcholine micelles by solution NMR spectroscopy. Magnetically aligned unflipped bicelle samples were used to investigate the structure and topology of LPcin-I and LPcin-II by solid-state NMR spectroscopy.
Citation: 3

Proteolytic activation of proteose peptone component 3 by release of a C-terminal peptide with antibacterial properties

Cited Entries: LAP0001, LAP0004

Authors:Pedersen, L.R.L., Hansted, J.G., Nielsen, S.B., Petersen, T.E., S鷨ensen, U.S., Otzen, D., S鷨ensen, E. S.
Journal: Journal of Dairy Science 2012, 95(6): 11.
Abstract: The milk protein proteose peptone component 3 (PP3, also known as lactophorin) is a small phosphoglycoprotein, which is exclusively expressed in the lactating mammary gland. A 23-residue synthetic peptide (lactophoricin, Lpcin S), corresponding to the C-terminal amphipathic α-helix of PP3, has previously been shown to permeabilize membranes and display antibacterial activity. Lactophorin readily undergoes proteolytic cleavage in milk and during dairy processing, and it has been suggested that PP3-derived peptides are part of milk's endogenous defense system against bacteria. Here, we report that a 26-residue C-terminal peptide (Lpcin P) can be generated by trypsin proteolysis of PP3 and that structural and functional studies of Lpcin P indicate that the peptide has antibacterial properties. The Lpcin P showed α-helical structure in both anionic and organic solvents, and the amount of α-helical structure was increased in the presence of lipid vesicles. Oriented circular dichroism showed that Lpcin P oriented parallel to the membrane surface. However, the peptide permeabilized calcein-containing vesicles efficiently. Lpcin P displayed antibacterial activity against Streptococcus thermophilus, but not against Staphylococcus aureus and Escherichia coli. The PP3 full-length protein did not display the same properties, which could indicate that PP3 functions as a precursor protein that upon proteolysis, releases a bioactive antibacterial peptide.
Keywords: antibacterial peptide;antimicrobial activity;lactophoricin;proteose peptone component 3

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