2XHG
Crystal Structure of the Epimerization Domain from the Initiation Module of Tyrocidine Biosynthesis
Summary for 2XHG
| Entry DOI | 10.2210/pdb2xhg/pdb |
| Descriptor | TYROCIDINE SYNTHETASE A, GLYCEROL, SODIUM ION, ... (4 entities in total) |
| Functional Keywords | isomerase, nonribosomal peptide synthesis, cofactor-independent epimerization |
| Biological source | BREVIBACILLUS BREVIS |
| Total number of polymer chains | 1 |
| Total formula weight | 53460.79 |
| Authors | Samel, S.-A.,Heine, A.,Marahiel, M.A.,Essen, L.-O. (deposition date: 2010-06-15, release date: 2011-07-06, Last modification date: 2024-05-08) |
| Primary citation | Samel, S.-A.,Czodrowski, P.,Essen, L.-O. Structure of the Epimerization Domain of Tyrocidine Synthetase A Acta Crystallogr.,Sect.D, 70:1442-, 2014 Cited by PubMed Abstract: Tyrocidine, a macrocyclic decapeptide from Bacillus brevis, is nonribosomally assembled by a set of multimodular peptide synthetases, which condense two D-amino acids and eight L-amino acids to produce this membrane-disturbing antibiotic. D-Phenylalanine, the first amino acid incorporated into tyrocidine, is catalytically derived from enzyme-bound L-Phe by the C-terminal epimerization (E) domain of tyrocidine synthetase A (TycA). The 1.5 Å resolution structure of the cofactor-independent TycA E domain reveals an intimate relationship to the condensation (C) domains of peptide synthetases. In contrast to the latter, the TycA E domain uses an enlarged bridge region to plug the active-site canyon from the acceptor side, whereas at the donor side a latch-like floor loop is suitably extended to accommodate the αIII helix of the preceding peptide-carrier domain. Additionally, E domains exclusively harbour a conserved glutamate residue, Glu882, that is opposite the active-site residue His743. This active-site topology implies Glu882 as a candidate acid-base catalyst, whereas His743 stabilizes in the protonated state a transient enolate intermediate of the L↔D isomerization. PubMed: 24816112DOI: 10.1107/S1399004714004398 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.5 Å) |
Structure validation
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