Elucidation of the Primary Structure of the Lantibiotic Epilancin K7 from Staphylococcus epidermidis K7. Cloning and Characterisation of the Epilancin-K7-Encoding Gene and NMR Analysis of Mature Epilancin K7

Abstract

Elucidation of the primary structure of the lantibiotic epilancin K7 from Staphylococcus epidermidis K7. Cloning and characterisation of the epilancin-K7-encoding gene and NMR analysis of mature epilancin K7 Kamp, Mart van de; Hooven, Henno W. van den; Konings, Ruud N.H.; Bierbaum, Gabriele; Sahl, Hans-Georg; Kuipers, Oscar; Siezen, Roland J.; Vos, Willem M. de; Hilbers, Cornelis W.; Ven, Frank J.M. van de Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. Download date: 10-05-2018Eur. J. Biochem. 230, 587-600 (1995) Lantibiotics are bacteriocins that contain unusual amino acids such as lanthionines and a$-didehydro residues generated by posttranslational modification of a ribosomally synthesized precursor protein. The structural gene encoding the novel lantibiotic epilancin K7 from Staphylococcus epidemzidis K7 was cloned and its nucleotide sequence was determined. The gene, which was named elkA, codes for a 55-residue preprotein, consisting of an N-terminal 24-residue leader peptide, and a C-terminal 31 -residue propeptide which is posttranslationally modified and processed to yield mature epilancin K7. In common with the type-A lantibiotics nisin A and nisin Z , subtilin, epidermin, gallidermin and Peps, pre-epilancin K7 has a so-called class-A1 leader peptide. Downstream and upstream of the elk4 gene, the starts of two open-reading-frames, named elkP and elkT, were identified. The elkP and elkT genes presumably encode a leader peptidase and a translocator protein, respectively, which may be involved in the processing and export of epilancin K7. The amino acid sequence of the unmodified pro-epilancin K7, deduced from the elkA gene sequence, is in full agreement with the amino acid sequence of mature epilancin K7, determined previously by means of NMR spectroscopy Biochern. 227, 757-7711. The first residue of mature epilancin K7 appears to be modified in a way that has not been described for any other lantibiotic so far. NMR experiments show that the elkA-encoded serine residue at position + I of pro-epilancin K7 is modified to a 2-hydroxypropionyl residue in the mature protein.

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“…Although the mode of action of epilancin family bacteriocins is unknown, it is believed that the ring structure and N-terminal lactate play an important role in the activity observed. The amino acid sequence composing the regions associated with the formation of these key structures appears conserved in the mature epilancin E core peptide, and they align with those reported in the 15X and K7 peptides [28,49]. Due to the presence of these conserved regions and the high percentage identity matched epilancin E shares with 15X and epilancin K7, the mature peptide was predicted to have the same structure and inhibition spectrum.…”

“…The gene encoding the core peptide was previously reported by Angelopoulou et al [29], though it had not been purified or characterized at the time of this study. The mass of epilancin E is predicted to be 2982 Da, which is lower than that of 15X and K7, which have reported masses of 3172 Da and 3032 Da, respectively [28,49]. Although the mode of action of epilancin family bacteriocins is unknown, it is believed that the ring structure and N-terminal lactate play an important role in the activity observed.…”