Determination of Alkyl‐Donor Promiscuity of Tyrosine‐O‐Prenyltransferase SirD from Leptosphaeria maculans

• Published in: Chembiochem : a European journal of chemical biology 2017-12, Vol.18 (23), p.2323-2327
• Main Authors: Bandari, Chandrasekhar, Scull, Erin M., Masterson, Johanna M., Tran, Rachel H. Q., Foster, Steven B., Nicholas, Kenneth M., Singh, Shanteri
• Format: Article
• Language: English
• Subjects: Alkylation; Ascomycota - enzymology; Binding Sites; Biocatalysis; Biocatalysts; Catalytic Domain; Chemical reactions; Dimethylallyltranstransferase - genetics; Dimethylallyltranstransferase - metabolism; Diphosphates - chemistry; Diphosphates - metabolism; Fungal Proteins - genetics; Fungal Proteins - metabolism; Hydrogen Bonding; Interrogation; Kinetics; Magnetic Resonance Spectroscopy; Molecular Dynamics Simulation; natural products; Prenyltransferases; Recombinant Proteins - biosynthesis; Recombinant Proteins - isolation & purification; sirodesmin; Substrate Specificity; Substrates; Tryptophan - metabolism; Tyrosine; Tyrosine - metabolism; unnatural donors
• ISSN: 1439-4227; 1439-7633
• DOI: 10.1002/cbic.201700469

Natural product prenyltransferases are known to display relaxed acceptor substrate specificity. Although recent studies with a small set of unnatural alkyl donors have revealed that prenyltransferases are flexible with regard to their alkyl donors, the scope of their alkyl donor specificity remains poorly understood. Towards this goal, we report the synthesis of 20 unnatural alkyl pyrophosphate donors and an assessment of the reactions of these synthetic unnatural alkyl pyrophosphate analogues catalyzed by tyrosine O‐prenyltransferase SirD. This study demonstrates that SirD can utilize 16 out of 21 alkyl pyrophosphate analogues (including the natural donor) in catalyzing mostly O‐alkylation of l‐tyrosine. This study reveals the broad alkyl donor specificity of SirD and opens the door for the interrogation of the alkyl donor specificity of other prenyltransferases for potential utility as biocatalysts for differential alkylation applications. The alkyl donor scope of tyrosine‐O‐prenyltransferase SirD has been determined by use of 21 synthetic alkyl pyrophosphate analogues, and the corresponding O‐alkylated tyrosine products have been characterized by NMR. The study highlights SirD as highly promiscuous towards unnatural alkyl donors and provides insight into steric factors that impact the alkyl chain selectivity.