About Anthrogen Anthrogen is engineering post-modality biology. Today's modalities reflect historical contingencies in biological progress, not fundamental categories. We develop the AI systems that design modular biological machines and the experimental infrastructure to instantiate them. We're a small, high-density team in San Francisco building frontier AI and the biological systems to validate it, and we care most about people who move fast, go deep, and pick up whatever the problem needs. The role We want experimental scientists with strong biological intuition and the ability to turn an uncertain question into a decisive experiment. You'll own research on how our designed proteins and assemblies behave: how they function, how they interact, and why they fail. That means developing the assays as well as choosing what to measure, and following a result far enough to understand it. Platform Science is not a queue of validation requests from the modeling team. You'll help decide which biological problems we tackle and what evidence would constitute progress. We care about research taste and experimental depth, not whether your previous work fits a particular modality. What you'll do • Drive experimental research from the initial question through assay design, execution, analysis, and the next design decision. • Build quantitative biochemical and functional assays for designed proteins and their assemblies, including experiments in relevant cellular contexts. • Distinguish real biological activity from assay artifacts through appropriate controls and independent measurements. • Work closely with ML researchers to turn successes and failures into useful constraints for the next generation of designs. • Develop methods that remain reliable across constructs, targets, and repeated experiments, and help colleagues use them well. Who you are • You have a track record of original experimental research and can explain what you personally figured out. That might be a strong paper, a difficult discovery program, or a method other scientists rely on. • You have deep hands-on expertise in protein biochemistry, molecular biology, cell biology, or a closely related field, and the fundamentals to work beyond your specialty. • You can build and troubleshoot an assay, reason quantitatively about its limitations, and recognize when a clean-looking result is misleading. • You drive a research direction independently while staying close to the bench. You document your work well enough that someone else can reproduce it. • You are curious, high-agency, and willing to change your mind when the experiment disagrees with you. Bonus points • Experience characterizing engineered proteins or complex protein systems. • Experience investigating protein function and mechanism in cellular systems. • Experience connecting structural or biophysical measurements to function. • Python or R for analysis, or experience with high-throughput experimentation and lab automation. Logistics Full-time, onsite in San Francisco. Equity: 0.05-0.5%.