The Role
We are seeking a highly motivated and versatile Scientist I to join our Design Hypothesis Testing team. In this role, you will drive the end-to-end process of recombinant protein production — from construct design and molecular cloning through expression, purification, and biophysical characterization. Your work will directly support discovery programs by delivering high-quality protein reagents and generating quantitative insights into molecular interactions.
You will collaborate closely with cross-functional teams, including AI scientists, biologists, and assay developers, to optimize protein workflows, troubleshoot production challenges, and develop scalable, high-throughput systems. This is an opportunity to build integrated expertise across molecular biology, protein biochemistry, and biophysical analysis within a dynamic, interdisciplinary environment.

Responsibilities

• Design and cloning: Design and generate expression constructs (gene synthesis, codon optimization, vector cloning, mutagenesis) to support protein engineering and reagent generation.
• Expression: Express recombinant proteins in multiple systems (E. coli, mammalian, cell-free, etc), optimizing yield and solubility.
• Purification: Purify proteins using chromatographic methods (affinity, ion exchange, size exclusion, etc.) and ensure reproducibility, purity, and stability.
• Protein characterization: Assess protein quality (SDS-PAGE, aSEC, etc), binding properties (BLI, ELISA, etc), and developability properties (ELISA, HIC, etc)
• Biophysical analysis: Design and execute binding and kinetic studies using BLI (Octet/Gator) and/or SPR (Biacore). Analyze sensorgrams, fit binding models, and determine kinetic constants (kon, koff, KD).
• Optimization and troubleshooting: Identify and address challenges related to expression, aggregation, or stability, and implement optimization strategies.
• High-throughput support: Contribute to automation or parallelized expression/purification workflows to enable rapid protein generation.
• Collaboration and documentation: Maintain rigorous electronic lab notebook records, manage reagent inventory, communicate results clearly to cross-functional teams, and contribute to SOP development and continuous workflow improvements.

Qualifications

Required

• Ph.D. in Biochemistry, Molecular Biology, Structural Biology, Protein Engineering, or a related discipline with 0–2 years of postdoctoral or industry experience; or
   B.S./B.A. in a relevant field with 8–10 years of hands-on laboratory experience in protein expression and purification.
• Demonstrated expertise in recombinant protein expression and purification across multiple host systems.
• Expertise with BLI (Octet/Gator) or SPR (Biacore) instrumentation, data analysis, and assay optimization.
• Proficiency in molecular cloning (PCR, Gibson, Golden Gate, mutagenesis) and expression construct design.
• Strong problem-solving skills and ability to troubleshoot independently across molecular and biophysical workflows.
• Excellent organization, record-keeping (ELN), and communication skills.
• Comfortable managing multiple projects in a collaborative, fast-paced research environment.

Preferred

• Familiarity with automation or high-throughput expression/purification pipelines.
• Hands-on experience with chromatography systems (e.g., ÄKTA) and analytical methods (HPLC, MS).
• Understanding of protein stability, aggregation, and formulation principles.

Compensation

We offer a competitive compensation and benefits package, seeking to provide an open, flexible, and friendly work environment to empower employees and provide them with a platform to develop their long-term careers. A Summary of Benefits is available for all applicants. We offer a competitive package that includes base salary, bonus, and equity. The base pay range for this position is expected to be $110,000 - $138,000 annually; however, the base pay offered may vary depending on the market, job-related knowledge, skills and capabilities, and experience.

Xaira Therapeutics an equal-opportunity employer. We believe that our strength is in our differences. Our goal to build a diverse and inclusive team began on day one, and it will never end.

TO ALL RECRUITMENT AGENCIES: Xaira Therapeutics does not accept agency resumes. Please do not forward resumes to our jobs alias or employees. Xaira Therapeutics is not responsible for any fees related to unsolicited resumes.