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PP3 f(110-135) [id=LAP0004]

Synonym: Lactophoricin P ; Lpcin P

Producer Organism : Native Protein : Production Method :
Cow PP3 Enzymatic hydrolysis and Purification with LC method
Activity : Antibacterial
Target Organisms :

Gram-positive: Streptococcus thermophilus AFI08 (MIC=22 然 or IC50=1.1 然).

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

Description :
Production method: Trypsin hydrolysis and purification with LC method.
Length : 26 Mass (Da): 3 039.68 Common Amino Acids : K
Isolectric Point : 9.19 Net Charge : 2 Absent Amino Acids : CDGMPQRW
Basic Residues : 5 Acidic Residues : 3 Hydrophobic Residues : 10
Polar Residues : 8 Boman Index : -35.65 Hydropathy Index : -0.208
Aliphatic Index : 97.31 Instability Index : 0 Extinction Coefficient : 1490
Absorbance 280nm : 59.6

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

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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