An iterative, bimodular nonribosomal peptide synthetase that converts anthranilate and tryptophan into tetracyclic asperlicins
- Gao, X. 2
- Jiang, W. 1
- Jiménez-Osés, G. 2
- Choi, M.S. 2
- Houk, K.N. 2
- Tang, Y. 2
- Walsh, C.T. 1
- 1 Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, United States
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2
University of California Los Angeles
info
ISSN: 1074-5521
Año de publicación: 2013
Volumen: 20
Número: 7
Páginas: 870-878
Tipo: Artículo
beta Ver similares en nube de resultadosOtras publicaciones en: Chemistry and Biology
Resumen
The bimodular 276 kDa nonribosomal peptide synthetase AspA from Aspergillus alliaceus, heterologously expressed in Saccharomyces cerevisiae, converts tryptophan and two molecules of the aromatic β-amino acid anthranilate (Ant) into a pair of tetracyclic peptidyl alkaloids asperlicin C and D in a ratio of 10:1. The first module of AspA activates and processes two molecules of Ant iteratively to generate a tethered Ant-Ant-Trp-S-enzyme intermediate on module two. Release is postulated to involve tandem cyclizations, in which the first step is the macrocyclization of the linear tripeptidyl-S-enzyme, by the terminal condensation (CT) domain to generate the regioisomeric tetracyclic asperlicin scaffolds. Computational analysis of the transannular cyclization of the 11-membered macrocyclic intermediate shows that asperlicin C is the kinetically favored product due to the high stability of a conformation resembling the transition state for cyclization, while asperlicin D is thermodynamically more stable. © 2013 Elsevier Ltd.