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Max Jordan @maxljordan.bsky.social · 16/09/2026

It was great to speak about our recent work on NLRs in Streptomyces at BacNet this week! An extremely friendly meeting packed with great science, and the location isn't too bad either!

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Reposted by Max Jordan

Delfi Dorussen @delfidorussen.bsky.social · 04/09/2026

Really cool work from @maxljordan.bsky.social @s-lab.bsky.social out on bioRXiv today! Find out more about how engineering NLRs in bacteria can enhance the production of antibiotics and anti-cancer drugs 👇🧬🧫

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Reposted by Max Jordan

Susan Schlimpert @s-lab.bsky.social · 04/09/2026

NLRs aren't just for immunity. Inspired by our colleagues working on plant NLRs, postdoc @maxljordan.bsky.social from my lab asked: Do bacterial NLR-type regulators found in antibiotic-producing #Streptomyces share a similar autoactivation switch? Turns out, yes! Read the full story and his 🧵👇

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Max Jordan @maxljordan.bsky.social · 04/09/2026

Of course, most crucially the support from Susan Schlimpert (@s-lab.bsky.social) over the years that I’ve been in her lab working on AfsR and Streptomyces NLRs! Very happy with how this all came together! (17/17)

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Max Jordan @maxljordan.bsky.social · 04/09/2026

Metabolomics was a whole new (slightly overwhelming) area for me! A collaboration with Natalia Miguel Vior (@anazaris.bsky.social) and Andy Truman (@andytruman4.bsky.social), who performed the LC-MS and analysis, made this possible! (16/17)

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Max Jordan @maxljordan.bsky.social · 04/09/2026

Matt Bush offered critical help across the board - particularly with protein purification, ChIP-seq and RNA-seq! Govind Chandra performed crucial analysis of RNA-seq and ChIP-seq data. (15/17)

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Max Jordan @maxljordan.bsky.social · 04/09/2026

This work wouldn’t have been possible without all of my wonderful co-authors! Hongrui Wang (@hongrui-wang.bsky.social) did some heroic work on the in vitro characterisation of AfsR binding, with input from Kathy Stratton (@kathystratton.bsky.social) and Abbas Maqbool! (14/17)

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Max Jordan @maxljordan.bsky.social · 04/09/2026

Overall, this work expands our understanding of NLR proteins outside of immunity and suggests a common autoinhibition/activation mechanism. Generating autoactive variants of NLRs like AfsR further offers a novel strategy for increasing production of critical antibiotics! (13/17)

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Max Jordan @maxljordan.bsky.social · 04/09/2026

We also identified thousands of additional AfsR-like regulators in Actinomycete genomes. These are encoded both inside BGCs and ‘ectopically’ elsewhere in the genome. Crucially, the MHD motif is highly conserved, demonstrating the potential of this approach to rewire metabolism! (12/17)

Panels A and B are histograms showing the presence of thousands of AfsR-like proteins in Streptomyces and Actinomycete genomes. Figure C shows that these proteins are both cluster-situated and encoded elsewhere in the genome. Panel D shows via alignment that the HD motif is highly conserved.

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Max Jordan @maxljordan.bsky.social · 04/09/2026

We first engineered autoactive Streptomyces peucetius AfsR - the strain which produces chemotherapy agents such as the ‘red devil’ doxorubicin. Peucemycins, a novel family of anticancer agents, are usually only produced under cold stress. Autoactive AfsR removes this requirement. (11/17)

LC-MS data showing that autoactive AfsR increases production of peucemycin and hydroxy-peucemycin.

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Max Jordan @maxljordan.bsky.social · 04/09/2026

Finally - we wanted to see how this autoactivity strategy could be applied more broadly to harness Streptomyces (and actinomycete) specialised metabolism 🤔 (10/17)

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Max Jordan @maxljordan.bsky.social · 04/09/2026

In the promoters of these two genes, there is a conserved motif. In vitro, AfsR binds specifically to these sequences, with autoactivity enhancing the affinity. In the case of wblH, we only observe binding with the autoactive AfsR variant. (9/17)

Top panel shows the conserved AfsR binding motif within the afsS and wblH promoters. Bottom panel shows specific binding of AfsR to this site - with this binding enhanced with autoactive AfsR.

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Max Jordan @maxljordan.bsky.social · 04/09/2026

Is AfsR regulating these BGCs directly? In our transcriptomics data we also observe strong upregulation genes encoding two transcriptional regulators - afsS and wblH. ChIP-seq suggests these represent the only direct AfsR targets in vivo! (8/17)

ChIP-seq traces covering the afsS and wblH promoters. AfsR binding is observed at both.

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Max Jordan @maxljordan.bsky.social · 04/09/2026

Using transcriptomics, we observe an upregulation of multiple biosynthetic gene clusters (BGCs) upon AfsR autoactivation - including the otherwise silent coelimycin. Untargeted metabolomics confirms overproduction of these molecules as well! (7/17)

First panel shows upregulation of genes associated with antibiotic production using RNA-seq. Second panel shows corresponding overproduction of the associated molecules using LC-MS.

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Max Jordan @maxljordan.bsky.social · 04/09/2026

This suggests that the MHD motif is a conserved component of NLR autoinhibition and activation across the tree of life! But can we use this to characterise the downstream signalling that leads to antibiotic production? 🤔 (6/17)

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Max Jordan @maxljordan.bsky.social · 04/09/2026

Strikingly, the MHD motifs histidine and aspartic acid are almost universally conserved in AfsR! In AfsR from the model Streptomyces coelicolor, mutagenesis of these residues induced striking overproduction of the blue antibiotic actinorhodin! AfsR(GV) is now autoactive! (5/17)

Figure from the preprint. Top panel shows the postion of the MHD motif in the AfsR protein. The central demonstrates through alignment it's conservation. Bottom panel shows via production of actinorhodin that mutation of this motif induces autoactivity.

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Max Jordan @maxljordan.bsky.social · 04/09/2026

This is the case in AfsR - a well-conserved global regulator of Streptomyces antibiotic production. Can we rationally engineer a constitutively active version to escape this bottleneck? In plant NLRs, mutation of the ‘MHD motif’ induces autoactivity. (4/17)

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Max Jordan @maxljordan.bsky.social · 04/09/2026

Surprisingly, this antibiotic production is often transcriptionally regulated by NLRs - molecular switches usually associated with immunity. NLRs are inactive until recognition of an activating signal - if you don’t know the signal, it is hard to characterise their mechanism 🤔 (3/17)

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Max Jordan @maxljordan.bsky.social · 04/09/2026

Streptomyces produce diverse metabolites extensively utilised in the clinic including antibiotics and anti-cancer agents. Understanding how their production is regulated remains a key challenge - particularly how we can induce production of specific compounds under lab conditions. (2/17)

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