HIV Protease Inhibitors Block Streptolysin S Production

Abstract

Streptolysin S (SLS) is a post-translationally modified peptide cytolysin that is produced by the human pathogen Streptococcus pyogenes. SLS belongs to a large family of azole-containing natural products that are biosynthesized via an evolutionarily conserved pathway. SLS is an important virulence factor during S. pyogenes infections, but despite an extensive history of study, further investigations are needed to clarify several steps of its biosynthesis. To this end, chemical inhibitors of SLS biosynthesis would be valuable tools to interrogate the various maturation steps of both SLS and biosynthetically-related natural products. Such chemical inhibitors could also potentially serve as anti-virulence therapeutics, which in theory may alleviate the spread of antibiotic resistance. In this work, we demonstrate that FDA-approved HIV protease inhibitors, especially nelfinavir, block a key proteolytic processing step during SLS production. This inhibition was demonstrated in live S. pyogenes cells and through in vitro protease inhibition assays. A panel of 57 nelfinavir analogs was synthesized, leading to a series of compounds with improved anti-SLS activity while illuminating structure-activity relationships. Nelfinavir was also found to inhibit the maturation of other azole-containing natural products, namely those involved in listeriolysin S, clostridiolysin S, and plantazolicin production. The use of nelfinavir analogs as inhibitors of SLS production has allowed us to begin examining the proteolysis event in SLS maturation and will aid in further investigations of the biosynthesis of SLS and related natural products.

Precursor peptide-targeted mining of more than one hundred thousand genomes expands the lanthipeptide natural product family

“…6B). Unlike class III lanthipeptide gene clusters from Actinobacteria that usually do not contain a protease [77], the III 3 clusters encode for a prolyl oligopeptidase (we propose the name LanP B for these with the name LanP A given to the previously characterized group of subtilisin-like leader peptide proteases [11]) as well as a CAAX family protease [78]. The smaller III 6 family is also found in Firmicutes but the phylogenetic distribution is more varied as these BGCs are found in different Bacillus and Staphylococcus species.…”

YcaO-Dependent Posttranslational Amide Activation: Biosynthesis, Structure, and Function

“…By homology to SagE, the previously described type II CaaX-like protease, BamE was hypothesized to remove the leader. 138 Additionally, methylation was anticipated based on the presence of a S -adenosylmethionine (SAM)-dependent methyltransferase (BamL). This methyltransferase was later shown to selectively dimethylate the newly formed N-terminus of PZN through a narrow substrate tunnel which limited access to the active site.…”

In Vitro Biosynthesis and Substrate Tolerance of the Plantazolicin Family of Natural Products

“…The C-protein serves to bind the N -terminal (leader) region of the precursor peptide, enhancing the rate of processing (12–14). Following heterocyclization, the biosynthesis of PZN is completed by removal of the leader peptide, likely by the locally encoded type II CaaX protease (15, 16), and dimethylation of the new N -terminus by an S- adenosylmethionine (SAM)-dependent methyltransferase (17, 18). …”