Principal Scientist, Protein Engineering

Xaira Therapeutics•South San Francisco, CA
•$164,000 - $205,000•Onsite

About The Position

As a member of the Protein Engineering team at Xaira, you will play a critical role in the AI-driven discovery and development of protein therapeutics, integrating experimental protein engineering with computational design. As a Principal Scientist, you will provide scientific and technical leadership from program conception through early discovery and lead optimization. You will partner closely with computational protein designers to guide AI-driven design campaigns and develop experimental strategies to evaluate designed molecules. You will engineer, produce, and characterize therapeutic proteins and antibodies, with an emphasis on optimizing functional properties and developability. This is a hands-on, lab-based, on-site position with significant program leadership responsibilities.

Requirements

  • Ph.D. in a relevant scientific discipline, with a strong foundation in molecular biology, biochemistry, structural biology, or a related field.
  • At least 6 years of industry experience in biotech or biopharma R&D supporting large-molecule therapeutic programs.
  • Extensive hands-on experience in protein engineering, including structural and functional characterization of antibodies and other proteins using advanced analytical methods.
  • Deep expertise in antibody formats, production, purification, and characterization.
  • Proficiency in developability assessments and stability studies.
  • Proficiency with protein visualization and structure prediction tools, such as PyMOL and AlphaFold.
  • Strong organizational, communication, and interpersonal skills.
  • Ability to propose novel scientific approaches and a strong interest in exploring relevant therapeutic hypotheses.
  • A proactive, self-directed approach, with excellent problem-solving and troubleshooting skills.
  • Enthusiasm for working in a fast-paced, collaborative startup environment, with a demonstrated ability to promote cooperation and knowledge sharing across multidisciplinary teams.
  • A strong record of scientific achievement, demonstrated by first-author publications in peer-reviewed journals or granted patents.

Nice To Haves

  • Direct experience with structure prediction or machine learning tools for protein design is preferred.
  • Experience collaborating with Process Development and supporting IND documentation is nice to have.

Responsibilities

  • Define the scientific strategy for one or more therapeutic programs in partnership with the Disease Biology and Therapeutic Protein Design teams. Contribute to the evaluation of novel targets, define therapeutic hypotheses and target product profiles, and develop integrated, AI-driven drug discovery strategies.
  • Work closely with computational protein designers to identify relevant structural and biological features of therapeutic targets and incorporate these insights into design campaigns.
  • Lead binder discovery campaigns, working closely with internal teams to prioritize screening strategies, interpret results, and identify hits.
  • Collaborate with protein designers to develop and execute strategies to optimize binder affinity, specificity, and developability.
  • Serve as a scientific lead in cross-functional program meetings, communicating protein engineering strategy and progress to internal stakeholders
  • Design, produce, purify, and characterize therapeutic proteins, including antibodies, using chromatographic techniques and biophysical and biochemical assays.
  • Maintain accurate, timely, and complete experimental records in an electronic laboratory notebook (ELN).
  • Contribute to the preparation of technical reports, regulatory documentation, and scientific presentations.
  • Ensure compliance with laboratory safety protocols and contribute to laboratory organization and operational efficiency.
  • Stay current with advances in antibody engineering and protein design, and apply these insights to help shape the team’s scientific direction.
  • Mentor and develop junior scientific staff, supporting a high-performing, collaborative team.
  • Oversee CROs supporting outsourced work, ensuring data quality and timely delivery.
  • Help define and prioritize the Protein Engineering team’s project portfolio in collaboration with leadership.

Benefits

  • competitive compensation and benefits package
  • open, flexible, and friendly work environment
  • platform to develop their long-term careers
  • competitive package that includes base salary, bonus, and equity

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What This Job Offers

Job Type

Full-time

Career Level

Principal

Education Level

Ph.D. or professional degree

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