Casecidin 15 [id=CAB0007]

Synonym: Beta-casein f(193-207)

Producer Organism : Native Protein : Production Method :
Cow β-casein Acetic acid treatment and Purification
Activity : Antibacterial
Target Organisms :

Gram-negative: Escherichia coli DH5alpha (MIC=0.4 mg/ml), Escherichia coli DPC 6053 (MIC=0.5 mg/ml).

NOTE: No activity against Enterobacter sakazakii FAIR DPC 5120 (>1 mg/ml) .

Description :
Production method: Acetic acid treatment and purification.

Length : 15 Mass (Da): 1 669.33 Common Amino Acids : P
Isolectric Point : 6.4 Net Charge : Absent Amino Acids : ACDHKMNSTW
Basic Residues : 1 Acidic Residues : 1 Hydrophobic Residues : 5
Polar Residues : 3 Boman Index : -4.63 Hydropathy Index : -0.033
Aliphatic Index : 90.67 Instability Index : 0 Extinction Coefficient : 1490
Absorbance 280nm : 106.43

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

Antimicrobial activity of two peptides casecidin 15 and 17, found naturally in bovine colostrum

Cited Entries: CAA0002, CAB0007, CAB0008

Authors:Birkemo, G., O'Sullivan, O., Ross, R., Hill, C.
Journal: Journal of Applied Microbiology 2009, 106(1).
Abstract: Aims:  To isolate and characterize peptides from bovine colostrum with antimicrobial activity. Methods and Results:  Three peptides were purified from fresh colostrum by a range of chromatographic methods using antimicrobial activity against Escherichia coli DH5α to screen for the most active fractions. Two peptides, with antimicrobial activity, casecidin 17 and casecidin 15, were identical to sequences in the C-terminal of bovine β-casein (YQEPVLGPVRGPFPIIV and YQEPVLGPVRGPFPI) and had corresponding molecular masses of 188100 and 166906 Da, respectively. The third peptide was the known peptide isracidin which has a mass of 276380 Da and sequence of RPKHPIKHQGLPQEVLNENLLRF. Casecidin 17 and casecidin 15 had identical minimal inhibition concentrations (MICs) against E. coli DPC6053 of 04 mg ml−1. Structural modelling suggested amphiphilic structures having identical inhibitory and structural properties. The MIC value of isracidin against E. coli DPC6053 was 02 mg ml−1. Conclusions:  This study shows the presence of three antimicrobial peptides in colostrum which may contribute to a bioprotective role to limit pathogen contamination. Furthermore, the discovery of casecidin 17 and 15 may provide the basis for novel antimicrobial peptide design. Significance and Impact of the Study:  This is the first study to characterize peptides with antimicrobial activity present in fresh bovine colostrum.
Keywords: antimicrobial peptide; bovine; colostrum; isolation and identification

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