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Purification and structure of mutacin B-Ny266: a new lantibiotic produced by Streptococcus mutans
M Mota-Meira1, C Lacroix, G LaPointe
1Centre de Recherche en Sciences et Technologie du Lait (STELA), Faculté des Sciences de l'Agriculture et de l'Alimentation, Université Laval, Québec, Canada.
Abstract:
Mutacins are bactericidal substances of proteinaceous nature produced by Streptococcus mutans. Lantibiotics are antibacterial substances containing post-translationally modified amino acids such as lanthionine. Mutacin B-Ny266 was purified from the cell pellet of S. mutans strain Ny266 by ethanol extraction at pH 2.0 followed by reversed-phase chromatography (Sep-Pak cartridge) and by HPLC on a C18 column. The mean purification factor was 3240 +/- 81 and the mean yield was 1.0 +/- 0.1%. Molecular mass of mutacin B-Ny266 as determined by mass spectroscopy is 2270.29 +/- 0.21 Da. The amino acid sequence of the purified active fraction was obtained by Edman degradation after treatment with alkaline ethanethiol. Twenty-one amino acids were detected in this analysis. Mutacin B-Ny266 belongs to the type A lantibiotics. The proposed sequence is: F-K-A-W-U-F-A-Abu-P-G-A-A-K-O-G-A-F-N-U-Y-A. The molecule differs from that of epidermin/staphylococcin 1580 and gallidermin at positions 1, 2, 4, 5 and 6.
Insights
Researchers purified Mutacin B-Ny266, a lantibiotic from Streptococcus mutans, revealing its protein sequence and mass. This discovery advances understanding of these antibacterial protein compounds.
Area of Science:
- Microbiology
- Biochemistry
- Molecular Biology
Background:
- Mutacins are proteinaceous, bactericidal substances produced by Streptococcus mutans.
- Lantibiotics are a class of antibacterial compounds characterized by post-translational modifications, including lanthionine.
Purpose of the Study:
- To purify and characterize Mutacin B-Ny266 from Streptococcus mutans strain Ny266.
- To determine the molecular mass and amino acid sequence of Mutacin B-Ny266.
Main Methods:
- Purification involved ethanol extraction at pH 2.0, reversed-phase chromatography (Sep-Pak cartridge), and HPLC on a C18 column.
- Molecular mass was determined using mass spectrometry.
- Amino acid sequencing was performed via Edman degradation after alkaline ethanethiol treatment.
Main Results:
- Mutacin B-Ny266 was purified with a mean factor of 3240 +/- 81 and a yield of 1.0 +/- 0.1%.
- The molecular mass was determined to be 2270.29 +/- 0.21 Da.
- The proposed amino acid sequence is F-K-A-W-U-F-A-Abu-P-G-A-A-K-O-G-A-F-N-U-Y-A, identifying it as a type A lantibiotic.
- The sequence showed differences at specific positions compared to epidermin and gallidermin.
Conclusions:
- Mutacin B-Ny266 is a novel type A lantibiotic produced by Streptococcus mutans.
- The determined molecular mass and amino acid sequence provide crucial data for understanding lantibiotic structure-activity relationships.