Download MendeleyStructure and catalytic mechanism of a cyclic dipeptide prenyltransferase with broad substrate promiscuity.
Schuller, J.M., Zocher, G., Liebhold, M., Xie, X., Stahl, M., Li, S.M., Stehle, T.(2012) J Mol Biol 422: 87-99
- PubMed: 22683356
- DOI: https://doi.org/10.1016/j.jmb.2012.05.033
- Primary Citation of Related Structures:
4E0T, 4E0U - PubMed Abstract:
Fungal indole prenyltransferases (PTs) typically act on specific substrates, and they are able to prenylate their target compounds with remarkably high regio- and stereoselectivity. Similar to several indole PTs characterized to date, the cyclic dipeptide N-prenyltransferase (CdpNPT) is able to prenylate a range of diverse substrates, thus exhibiting an unusually broad substrate promiscuity. To define the structural basis for this promiscuity, we have determined crystal structures of unliganded CdpNPT and of a ternary complex of CdpNPT bound to (S)-benzodiazepinedione and thiolodiphosphate. Analysis of the structures reveals a limited number of specific interactions with (S)-benzodiazepinedione, which projects into a largely hydrophobic surface. This surface can also accommodate other substrates, explaining the ability of the enzyme to prenylate a range of compounds. The location of the bound substrates suggests a likely reaction mechanism for the conversion of (S)-benzodiazepinedione. Structure-guided mutagenesis experiments confirm that, in addition to (S)-benzodiazepinedione, CdpNPT can also act on (R)-benzodiazepinedione and several cyclic dipeptides, albeit with relaxed specificity. Finally, nuclear magnetic resonance spectroscopy demonstrates that CdpNPT is a C-3 reverse PT that catalyzes the formation of C-3β prenylated indolines from diketopiperazines of tryptophan-containing cyclic dipeptides.
Organizational Affiliation:
Interfakultäres Institut für Biochemie, Universität Tübingen, Hoppe-Seyler-Str. 4, 72076 Tübingen, Germany.
