Calin Plesa

Calin Plesa

@calin.bsky.social

Assistant Prof. @uoknightcampus.bsky.social. Cofounder @synplexity.bsky.social. Gene synthesis, synbio, protein engineering, nanopores, multiplex assays. Opinions my own. www.plesalab.org

1.4K followers941 following194 posts

Pinned

We just preprinted DropSynth-Gold where we replaced PCA with Golden Gate Assembly (GGA) inside emulsion droplets, extending multiplexed gene synthesis to ~3 kb constructs assembled from up to 12 fragments while preserving the scalability of DropSynth. 1/n

bioRxiv Synthetic Biology@biorxiv-synthbio.bsky.social

DropSynth-Gold: Golden Gate Assembly in Emulsions Extends Multiplexed Gene Libraries to Greater Lengths https://www.biorxiv.org/content/10.64898/2026.05.29.728538v1

We just preprinted DropSynth-Gold where we replaced PCA with Golden Gate Assembly (GGA) inside emulsion droplets, extending multiplexed gene synthesis to ~3 kb constructs assembled from up to 12 fragments while preserving the scalability of DropSynth. 1/n

bioRxiv Synthetic Biology@biorxiv-synthbio.bsky.social

DropSynth-Gold: Golden Gate Assembly in Emulsions Extends Multiplexed Gene Libraries to Greater Lengths https://www.biorxiv.org/content/10.64898/2026.05.29.728538v1

View full thread

Many GGA library assembly methods are limited by the number of orthogonal junctions that can coexist in a shared reaction. DropSynth-Gold performs each assembly in its own droplet. Library scale is determined primarily by barcode diversity, not junction diversity. 5/n

We just preprinted DropSynth-Gold where we replaced PCA with Golden Gate Assembly (GGA) inside emulsion droplets, extending multiplexed gene synthesis to ~3 kb constructs assembled from up to 12 fragments while preserving the scalability of DropSynth. 1/n

bioRxiv Synthetic Biology@biorxiv-synthbio.bsky.social

DropSynth-Gold: Golden Gate Assembly in Emulsions Extends Multiplexed Gene Libraries to Greater Lengths https://www.biorxiv.org/content/10.64898/2026.05.29.728538v1

View full thread

We kept everything that makes DropSynth scalable: barcoded bead capture, emulsion compartmentalization, and pooled processing, but replaced PCA with Type IIS Golden Gate Assembly inside droplets. 3/n

We benchmarked 6 libraries spanning 5-12 fragments per gene corresponding to lengths of ~1 kb to ~3 kb. GGA had comparable coverage and fidelity with a slight hit on uniformity. Fidelity (1 in ~1200 bp) remained stable across all lengths. 4/n

We just preprinted DropSynth-Gold where we replaced PCA with Golden Gate Assembly (GGA) inside emulsion droplets, extending multiplexed gene synthesis to ~3 kb constructs assembled from up to 12 fragments while preserving the scalability of DropSynth. 1/n

bioRxiv Synthetic Biology@biorxiv-synthbio.bsky.social

DropSynth-Gold: Golden Gate Assembly in Emulsions Extends Multiplexed Gene Libraries to Greater Lengths https://www.biorxiv.org/content/10.64898/2026.05.29.728538v1

Traditional DropSynth uses PCA, which becomes increasingly prone to cross-hybridization artifacts, partial assemblies, and amplification bias especially as fragment count increases. 2/n

Calin Plesa reposted

Just released! Fluorescent Protein Libraries from the Plesa Lab. Benchmarking protein expression, developing imaging tools, fluorescent protein engineering, and more. www.addgene.org/pooled-libra...

addgene.orgAddgene: Fluorescent Protein LibrariesUse to benchmark protein expression, develop imaging tools, or to serve as a starting point for fluorescent protein engineering.
Calin Plesa@calin.bsky.social

To enable reuse by the research community we're making the two parental FPBase libraries available on @addgene.bsky.social as pooled plasmid libraries (Addgene #245482 #245483). Use them. Shuffle them. Train on them! addgene.org/Calin_Plesa/ 12/n

New lab preprint: if ML struggles with extrapolation, let's expand the diversity of training data with gene synth, DNA shuffling, and ML gen.... also lots of #FluorescentProteins #ProteinEngineering #MachineLearning #SyntheticBiology 1/n

bioRxiv Synthetic Biology@biorxiv-synthbio.bsky.social

High Diversity Gene Libraries Facilitate Machine Learning Guided Exploration of Fluorescent Protein Sequence Space https://www.biorxiv.org/content/10.64898/2026.03.01.706892v1

View full thread

So if you want ML to explore distant optima, don’t just improve the model. Engineer the training distribution. Create diversity experimentally. Validate it functionally. Then let the model interpolate across it. 11/n

New lab preprint: if ML struggles with extrapolation, let's expand the diversity of training data with gene synth, DNA shuffling, and ML gen.... also lots of #FluorescentProteins #ProteinEngineering #MachineLearning #SyntheticBiology 1/n

bioRxiv Synthetic Biology@biorxiv-synthbio.bsky.social

High Diversity Gene Libraries Facilitate Machine Learning Guided Exploration of Fluorescent Protein Sequence Space https://www.biorxiv.org/content/10.64898/2026.03.01.706892v1

View full thread

Diversity metrics (clustering, k-mers, nearest-neighbor identity, mosaic structure, embedding geometry) show: 1) DNA shuffling expands dispersion 2) FACS constrains but preserves breadth 3) ML redistributes occupancy across new regions 9/n

ML-generated functional proteins show more mosaic structure than even the shuffled library. The model learns to recombine sequence segments across parental families in new ways (remixing at scale) 10/n

New lab preprint: if ML struggles with extrapolation, let's expand the diversity of training data with gene synth, DNA shuffling, and ML gen.... also lots of #FluorescentProteins #ProteinEngineering #MachineLearning #SyntheticBiology 1/n

bioRxiv Synthetic Biology@biorxiv-synthbio.bsky.social

High Diversity Gene Libraries Facilitate Machine Learning Guided Exploration of Fluorescent Protein Sequence Space https://www.biorxiv.org/content/10.64898/2026.03.01.706892v1

View full thread

We FACS sorted for blue fluorescence creating a high confidence 7,812 seq BFP training set. We fine tuned ProtGPT2 on this and generated 11,000 de novo sequences which were pruned for max diversity to set of 1,500 for synthesis. 7/n

We synthesized and screened them with hundreds of ML-generated proteins showing reproducible blue fluorescence. Some extend far beyond known natural clusters, including variants with <30% identity to any @fpbase.org protein. 8/n

New lab preprint: if ML struggles with extrapolation, let's expand the diversity of training data with gene synth, DNA shuffling, and ML gen.... also lots of #FluorescentProteins #ProteinEngineering #MachineLearning #SyntheticBiology 1/n

bioRxiv Synthetic Biology@biorxiv-synthbio.bsky.social

High Diversity Gene Libraries Facilitate Machine Learning Guided Exploration of Fluorescent Protein Sequence Space https://www.biorxiv.org/content/10.64898/2026.03.01.706892v1

View full thread

We next generated large numbers of new chimeric variants, that bridge distant homologs by DNA shuffling across the entire parental set. This synthetic recombination expanded sequence dispersion. 5/n

Even after heavy recombination, the β-barrel scaffold proved surprisingly robust. The shuffled library retained substantial fluorescence while increasing diversity 3x relative to parents. We expanded the manifold without collapsing function. 6/n

New lab preprint: if ML struggles with extrapolation, let's expand the diversity of training data with gene synth, DNA shuffling, and ML gen.... also lots of #FluorescentProteins #ProteinEngineering #MachineLearning #SyntheticBiology 1/n

bioRxiv Synthetic Biology@biorxiv-synthbio.bsky.social

High Diversity Gene Libraries Facilitate Machine Learning Guided Exploration of Fluorescent Protein Sequence Space https://www.biorxiv.org/content/10.64898/2026.03.01.706892v1

View full thread

We hypothesized that by experimentally expanding sequence diversity, we could convert extrapolation into interpolation by expanding the known manifold. 3/n

Using β-barrel fluorescent proteins (FPs) as a model, we synthesized a large fraction of the known β-barrel FPs from @fpbase.org (620 seqs), in two codon versions using DropSynth resulting in two large parental libraries spanning natural diversity. 4/n

New lab preprint: if ML struggles with extrapolation, let's expand the diversity of training data with gene synth, DNA shuffling, and ML gen.... also lots of #FluorescentProteins #ProteinEngineering #MachineLearning #SyntheticBiology 1/n

bioRxiv Synthetic Biology@biorxiv-synthbio.bsky.social

High Diversity Gene Libraries Facilitate Machine Learning Guided Exploration of Fluorescent Protein Sequence Space https://www.biorxiv.org/content/10.64898/2026.03.01.706892v1

PLMs do best when interpolating within known sequence space. But many protein families are sparsely sampled. Also global fitness optima may reside in distant regions of sequence space far from well studied seqs. So many design problems are extrapolative. 2/n

View full thread

Computational & Data-Science Neuroengineering: neural signal processing and analytics, closed-loop behavior tracking, neuromorphic computing and brain-inspired AI, spatial multi-omics analysis ...3/n

The BioE dept in the Knight Campus is a great place to work and is unique in many ways! We are expanding over the next few years with our second building opening in 2026. Come join us, applications begin review on October 15. ...4/n

Experimental & Translational Neuroengineering: neural interfaces, neurophotonics for brain stimulation/recording/imaging, pre-clinical bioelectric medicine or brain injury repair models, brain organoid technology, disease models ...2/n

Calin Plesa reposted

Our new Science Advances paper is out! 🎉 The Plesa Lab's first, it builds on DropSynth technology as a proof of concept for large-scale synthetic gene libraries, showcasing a synthetic metagenomics approach to studying antibiotic resistance at scale. 👉 www.science.org/doi/10.1126/...

science.orgExploring antibiotic resistance in diverse homologs of the dihydrofolate reductase protein family through broad mutational scanningDropSynth technology enables scalable and cost-effective exploration of antibiotic resistance across the DHFR protein family.

Huge congrats to Dr. Andrew Holston on a successful PhD defense!! Andrew has been working on the large-scale characterization and engineering of chimeric receptor histidine kinases. He’s looking for roles in biotech/academia, let’s connect if you’re hiring! -> @hkalltheway.bsky.social

Join us tomorrow, May 23, for Andrew Holston’s PhD thesis defense. Andrew is a graduate student in @calin.bsky.social’s lab, where his research has focused on the large-scale engineering of chimeric histidine kinases. 🧪

Calin Plesa reposted

Have we hit a "scaling wall" for protein language models? 🤔 Our latest ProteinGym v1.3 release suggests that for zero-shot fitness prediction, simply making pLMs bigger isn't better beyond 1-4B parameters. The winning strategy? Combining MSAs & structure in multimodal models!