6PGN

A Single Amino Acid Switch Alters the Isoprene Donor Specificity in Ribosomally Synthesized and Post-Translationally Modified Peptide Prenyltransferases

(2018) J Am Chem Soc 140: 8124-8127

• PubMed: 29924593 Search on PubMedSearch on PubMed Central
• DOI: https://doi.org/10.1021/jacs.8b05187
• Primary Citation of Related Structures:  
  6PGM, 6PGN


• PubMed Abstract: 
  

  Mutation at a single amino acid alters the isoprene donor specificity of prenyltransferases involved in the modification of ribosomally synthesized and post-translationally modified peptides (RiPPs). Though most characterized RiPP prenyltransferases carry out the regiospecific transfer of C ₅ dimethylallyl donor to the side chain atoms on macrocyclic acceptor substrates, the elucidation of the cyanobactin natural product piricyclamide 70005E1 identifies an O-geranyl modification on Tyr, a reaction with little prior biochemical precedence. Reconstitution and kinetic studies of the presumptive geranyltransferase PirF shows that the enzyme utilizes a C ₁₀ donor, with no C ₅ transferase activity. The crystal structure of PirF reveals a single amino acid difference in the vicinity of the isoprene-binding pocket, relative to the C ₅ utilizing enzymes. Remarkably, only a single amino acid mutation is necessary to completely switch the donor specificity from a C ₅ to a C ₁₀ prenyltransferase, and vice versa. Lastly, we demonstrate that these enzymes may be used for the chemospecific attachment of C ₅ or C ₁₀ lipid groups on lanthipeptides, an unrelated class of RiPP natural products. These studies represent a rare example where prenyl donor specificity can be discretely altered, which expands the arsenal of synthetic biology tools for tuning biological activities of peptide natural products.

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Organizational Affiliation: 

Department of Medicinal Chemistry , University of Utah , Salt Lake City , Utah 84112 , United States.