2MWR

Solution Structure of Acidocin B, a Circular Bacteriocin from Lactobacillus acidophilus M46

Summary for 2MWR

• Entry DOI: 10.2210/pdb2mwr/pdb
• NMR Information: BMRB: 25352
• Descriptor: Acidocin B (1 entity in total)
• Functional Keywords: circular bacteriocin, cyclic peptide, class ii, helical peptide, antimicrobial protein
• Biological source: Lactobacillus acidophilus
• Total number of polymer chains: 1
• Total formula weight: 5642.49

Authors

Vederas, J.C.,Acedo, J.Z.,van Belkum, M.J.,Lohans, C.T. (deposition date: 2014-11-19, release date: 2015-03-04, Last modification date: 2023-06-14)

Primary citation

Acedo, J.Z.,van Belkum, M.J.,Lohans, C.T.,McKay, R.T.,Miskolzie, M.,Vederas, J.C.
Solution Structure of Acidocin B, a Circular Bacteriocin Produced by Lactobacillus acidophilus M46.
Appl.Environ.Microbiol., 81:2910-2918, 2015

PubMed Abstract: Acidocin B, a bacteriocin produced by Lactobacillus acidophilus M46, was originally reported to be a linear peptide composed of 59 amino acid residues. However, its high sequence similarity to gassericin A, a circular bacteriocin from Lactobacillus gasseri LA39, suggested that acidocin B might be circular as well. Acidocin B was purified from culture supernatant by a series of hydrophobic interaction chromatographic steps. Its circular nature was ascertained by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry and tandem mass spectrometry (MS/MS) sequencing. The peptide sequence was found to consist of 58 amino acids with a molecular mass of 5,621.5 Da. The sequence of the acidocin B biosynthetic gene cluster was also determined and showed high nucleotide sequence similarity to that of gassericin A. The nuclear magnetic resonance (NMR) solution structure of acidocin B in sodium dodecyl sulfate micelles was elucidated, revealing that it is composed of four α-helices of similar length that are folded to form a compact, globular bundle with a central pore. This is a three-dimensional structure for a member of subgroup II circular bacteriocins, which are classified based on their isoelectric points of ∼7 or lower. Comparison of acidocin B with carnocyclin A, a subgroup I circular bacteriocin with four α-helices and a pI of 10, revealed differences in the overall folding. The observed variations could be attributed to inherent diversity in their physical properties, which also required the use of different solvent systems for three-dimensional structural elucidation.

PubMed: 25681186
DOI: 10.1128/AEM.04265-14

Experimental method

SOLUTION NMR