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Sam Carr

@carrsc.bsky.social
38 followers 61 following 5 posts

Plant molecular biology and biochemistry

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Reposted by Sam Carr
Science Magazine @science.org · 06/08/2026
A two-gene supergene and gravity work together to give butterfly lily flowers their rare floral left- and right-handedness, which improves pollen transfer, researchers report in Science. The findings offer new insight into the development of unique mirror-image flowers. scim.ag/4z22i6D
scim.ag
Supergene control of chiral development in mirror-image flowers
How genes determine the development of chiral structures is a fascinating question. The reciprocal placement of female and male organs on opposite sides of mirror-image flowers promotes efficient cros...
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Sam Carr @carrsc.bsky.social · 29/07/2026
www.science.org/doi/10.1126/...
science.org
Structural and mechanistic basis for the heterotetrameric benzaldehyde synthase from petunia
Heterotetrameric benzaldehyde synthase forms a composite α-β active site for benzaldehyde production.
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Reposted by Sam Carr
Nature Chemical Biology @natchembio.nature.com · 14/07/2026
Structures of cannabinoid cyclase show that bacterial and plant cyclases use distinct mechanisms for cannabinoid synthesis, and variants are engineered with improved stereocontrol www.nature.com/articles/s41...
nature.com
Structural and biochemical basis for cannabinoid cyclase activity in marine bacterial flavoenzymes - Nature Chemical Biology
Cannabinoid cyclases produce bioactive cannabinoids, but their mechanisms are poorly understood. Here the authors solve the substrate-bound structure of a cannabinoid cyclase, show that bacterial and ...
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Reposted by Sam Carr
Ryo Yokoyama @yokoyama-ryo.bsky.social · 06/07/2026
Cephalotaxinone enzymes reveal a whole plant model for homoharringtonine biosynthesis www.nature.com/articles/s41... @natchembio.nature.com
nature.com
Cephalotaxinone enzymes reveal a whole plant model for homoharringtonine biosynthesis - Nature Chemical Biology
Homoharringtonine (HHT) is a plant-derived anticancer drug approved by the US Food and Drug Administration. Here, the authors elucidate a root-tip-specific biosynthetic pathway to its alkaloid core, i...
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Reposted by Sam Carr
The Plant Journal @theplantjournal.bsky.social · 27/06/2026
🔎𝐏𝐞𝐫𝐬𝐩𝐞𝐜𝐭𝐢𝐯𝐞 🌱 Plant metabolism depends not only on what organelles do, but also on where they are Find it here👉 doi.org/10.1111/tpj.70987 ✍️ AR Fernie, G Decros, J Multhoff, J Sippel, JO Niemeier, P Barreto, A Sampathkumar, U Sonnewald, and M Schwarzländer
doi.org
PERSPECTIVE: organelle positioning as a principle of metabolic regulation and stress tolerance
Understanding how plant cells coordinate metabolism remains a major challenge, particularly at the level of intracellular organization. This perspective proposes that dynamic organelle positioning ac...
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Reposted by Sam Carr
rnett42.bsky.social @rnett42.bsky.social · 23/06/2026
In our new preprint, we report how clubmoss plants use an ancient biosynthetic pathway (>300 million years old!) to make huperzine A, an alkaloid with potential as a treatment for Alzheimer's disease. Great work by Eric Fields and @cyhkim.bsky.social www.biorxiv.org/content/10.6...
biorxiv.org
Ancient origins of alkaloid biosynthesis in medicinal clubmosses
The plant kingdom is rich with medicinal natural products that are complex and difficult to access. Discovering how plants build these molecules can be challenging, especially for biosynthetic pathway...
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Reposted by Sam Carr
Ryo Yokoyama @yokoyama-ryo.bsky.social · 19/06/2026
Transient dynamics of flavonoid metabolons tune chalcone synthase specificity www.nature.com/articles/s41... @natcatal.nature.com
nature.com
Transient dynamics of flavonoid metabolons tune chalcone synthase specificity - Nature Catalysis
Enzyme assemblies can enhance metabolic efficiency, yet the ways in which transient interactions fine tune catalytic outcomes remain poorly understood. This study demonstrates that a flexible partner ...
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Reposted by Sam Carr
Nature Biotechnology @natbiotech.nature.com · 19/06/2026
Efficient site-specific gene addition using R2 retrotransposons in tobacco and rice www.nature.com/articles/s41...
nature.com
Efficient site-specific gene addition using R2 retrotransposons in tobacco and rice - Nature Biotechnology
Retrotransposons are applied in plants for safe-harbor transgene integration.
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Sam Carr @carrsc.bsky.social · 16/06/2026
Happy to contribute to the biosynthetic pathway of Vinblastine and Ibogaine. We identified partner proteins that heterodimerize with the enzyme geissoschizine synthase to improve its activity and modulate stereochemical output. Read it in @pnas.org #PlantScience www.pnas.org/doi/10.1073/...
pnas.org
Tuning reductase activity in monoterpene indole alkaloid biosynthesis | PNAS
Monoterpene indole alkaloids encompass a diverse class of plant natural products. Many of these valuable compounds, including the anticancer medici...
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Sam Carr @carrsc.bsky.social · 01/06/2026
www.nature.com/articles/s41...
nature.com
Cellular water-potential sensing through biomolecular condensation - Nature
Plants sense water deficiency through SAM8 protein condensation, which responds to reduced hydration and triggers stress adaptation by altering RNA export and gene translation.
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Reposted by Sam Carr
Lichman Lab @lichmanlab.bsky.social · 18/05/2026
Pleased to share our full publication of our manuscript describing completion of nicotine biosynthesis in @natcomms.nature.com following our pre-print from December last year. In this work we solve the 200-year-old puzzle of how tobacco plants make nicotine. www.nature.com/articles/s41...
nature.com
Nicotine biosynthesis is completed by cryptic activating glucosylation - Nature Communications
Despite the significance of nicotine, a neuroactive alkaloid produced by tobacco, its biosynthesis has remained elusive. Here, the authors report the in vitro and in planta reconstruction of a fo...
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Reposted by Sam Carr
Keri Backus @keribackus.bsky.social · 03/05/2026
Super excited to launch POCAxOMAP with @dschweppe.bsky.social and @oligopain.bsky.social and led by Eli Biletch, Conor Herlihy and Lidan Li. If you’ve ever wanted to do proximity labeling on DNA, RNA, or protein without genetic engineering, look no further. www.biorxiv.org/content/10.6...
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Sam Carr @carrsc.bsky.social · 24/04/2026
The preprint for some recent work of mine is live. We show that the activity and product stereochemistry of a biosynthetic enzyme can be influenced through protein-protein interactions.
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Reposted by Sam Carr
Scientific American @sciam.bsky.social · 12/04/2026
Parasitic beetles are the first animals known to imitate floral scents
scientificamerican.com
These baby beetles work together to look—and smell—like flowers
Parasitic beetles are the first animals known to imitate floral scents
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Reposted by Sam Carr
Maite Colinas @maitecolinas.bsky.social · 11/04/2026
Our funky R-stereoselective Epi-STR is now available online and open access at its permanent home @angewandtechemie.bsky.social. 🥳 This is Clara's first first-author paper, makes me extra happy! @mpi-ce.bsky.social #PlantScience #natprod doi.org/10.1002/anie...
A collage showing on the left a picture of the  bright pink closed flowers and bracts of the plant Pogonopus speciosus. On the right a scheme depicting the reaction of tryptamine and secologanic acid to vincosidic acid that is catalyzed by P. speciosus Epi-STR, an unusual R-stereoselective ortholog of strictosidine synthase.
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Reposted by Sam Carr
Max Planck Institute for Chemical Ecology @mpi-ce.bsky.social · 18/03/2026
The process by which the cinchona tree produces quinine has been elucidated. In a new study published in @nature.com, researchers from the @oconnorlab.bsky.social and the @universityofga.bsky.social unveil the biosynthetic pathway behind this 400-year-old secret. www.ice.mpg.de/548102/PR_Ki...
ice.mpg.de
Mystery of quinine biosynthesis solved
For centuries, the process by which the cinchona tree produces its valuable alkaloids, including the life-saving quinine used to treat malaria, was shrouded in mystery. Now, a research team from the M...
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Reposted by Sam Carr
Maite Colinas @maitecolinas.bsky.social · 10/02/2026
In our latest preprint we report the unexpected discovery of Epi-STR, an R-stereoselective ortholog of the S-selective canonical Strictosidine synthases (STRs). Found in the rather obscure plant Pogonopus specious. This work was led by my stellar student Clara Morweiser! #natprod #PlantScience
Scheme showing the Pictet-Spengler reaction between tryptamine and a secoiridoid by canonical S-selective STRs compared to the newly discovered Epi-STR. On the right a photo of the pink flowers of Pogonopus speciosus. Photo taken by Eva Rothe.
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Reposted by Sam Carr
Nature @nature.com · 09/02/2026
Nature research paper: Single-molecule dynamics of the TRiC chaperonin system in vivo go.nature.com/4qZM3Cn
go.nature.com
Single-molecule dynamics of the TRiC chaperonin system in vivo - Nature
Single-particle tracking experiments in intact cells reveal dynamic co- and post-translational interactions of the TRiC–PFD chaperonin complex with client proteins during in vivo protein folding.
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Sam Carr @carrsc.bsky.social · 01/02/2026
Here, we explore the protein-protein interactions between monoterpene indole alkaloid biosynthetic enzymes. This work was the result of strong effort by Chloe Langley, who Allwin McDonald and I had the privilege to work with. Congrats to the team! ACS Chemical Biology pubs.acs.org/doi/full/10....
pubs.acs.org
Protein–Protein Interactions Modulate a Key Branch Point in Monoterpene Indole Alkaloid Biosynthesis
Biosynthetic pathways of specialized metabolites utilize protein–protein interactions (PPIs) to facilitate metabolic flux and sequester reactive intermediates. The monoterpene indole alkaloid pathway of Catharanthus roseus contains several metabolic branch points that may be mediated via transient PPIs. We investigated one branch point of this pathway that is responsible for the conversion of the intermediate dehydrosecodine into three possible cyclized alkaloid scaffolds, which act as intermediates en route to medicinally important alkaloids, such as vinblastine. We verified previously observed PPIs between reductase-cyclase pairs and additionally uncovered PPIs between evolutionarily related protein homologues. Through structural analysis of dehydrosecodine cyclases, we identified surface residues that appear to mediate interaction with the upstream reductase. We then demonstrated, via in vitro competition assays, that these residues impact the distribution of downstream products. These results highlight the significance of transient PPIs in the control and regulation of specialized metabolite pathways.
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