| Autor: |
Van De Kamp, Mart, Horstink, Leonard M., Van Den Hooven, Henno W., Konings, Ruud N. H., Hilbergs, Cornelis W., Frey, Angelika, Sahl, Hans-Georg, Metzger, Jörg W., Van De Ven, Frank J. M. |
| Předmět: |
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| Zdroj: |
European Journal of Biochemistry; 2/1/95, Vol. 227 Issue 3, p757-771, 15p |
| Abstrakt: |
The amino acid sequence of the novel lantibiotic epilancin K7 from Staphylococcus epidermidis K7 was determined by NMR spectroscopy. NMR spectroscopy was used because sequencing by conventional Edman degradation techniques was prohibited by internal sequence blocks owing to the presence of modified residues. Epilancin K7 consists of 31 residues, including two a,fl-didehydroalanine (one-letter code U) and two α,β-didehydrobutyrine (O) residues, one lanthionine (A-S-A), two β-methyllanthionines (A*-S-A), and six lysines. Epilancin K7 has a molecular mass of 3032 ± 1.5 Da. The amino acid sequence of epilancin K7 was derived from both through-space dipolar proton-proton interactions and through-bond scalar proton-carbon interactions as detected by two-dimensional ¹H-NOESY, ¹H-ROESY and three-dimensional ¹H-TOCSY-NOESY, and by two-dimensional ¹H,13C-heteronuclear multiple-bond correlation spectroscopy, respectively. The sequence is as follows: [This equation cannot be represented into ASCII Text] The N-terminal residue X partly resembles an alanine but its exact nature is unclear. The organization of the sulfide-bridge-containing (β-methyl-)lanthionines was revealed by ¹H-NMR and ¹H,13C-NMR spectroscopy. Epilancin K7 has a linear structure and a high positive net charge, and therefore is classified as a type-A lantibiotic. NMR analysis of a degraded though still active form of epilancin K7 showed that two N-terminal residues of epilancin K7 were missing, owing to decomposition at the α,β-didehydro alanine at position 3; it was called the epilancin K7-(3–31)-peptide (peptide fragment of epilancin K7 consisting of positions 3–31). The usefulness of three-dimensional ¹H-TOCSY-NOESY, and two-dimensional ¹H,13 C-heteronuclear multiple-bond correlation spectroscopy at natural abundance for the study of (modified) polypeptides is demonstrated. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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