Director, Protein Sciences

xairatherapeutics

South San Francisco, California, United States · South San Francisco · United States

Posted Jun 26, 2026

Other
Drug Discovery & Development

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Job description

About Xaira Therapeutics

Xaira is an innovative biotech startup focused on leveraging AI to transform drug discovery and development. The company is leading the development of generative AI models to design protein and antibody therapeutics, enabling the creation of medicines against historically hard-to-drug molecular targets. It is also developing foundation models for biology and disease to enable better target elucidation and patient stratification. Collectively, these technologies aim to continually enable the identification of novel therapies and to improve success in drug development. Xaira is headquartered in the San Francisco Bay Area, Seattle, and London.

About the Role
As the Director of Protein Sciences, you are the primary architect of the group's strategic vision. You will autonomously define, prioritize, and execute our protein production and characterization roadmap, proactively driving the protein design team to challenge conventional antibody assumptions and maximize platform innovation while aligning with clinical development objectives.

About You
You are a visionary leader who doesn't just manage the status quo—you proactively identify bottlenecks and implement innovative solutions to push our protein sciences capabilities forward. You cultivate a culture of scientific rigor, high performance, and rapid iteration. Taking pride in building and leading a protein sciences team that is at the forefront of protein production, characterization, and drug development. You enjoy mentoring and developing team members to have a passion for drug discovery and developing novel treatments for patients.

Responsibilities

Champion and drive cross-functional integration across diverse research teams—spanning biology, AI design, and engineering—to successfully achieve scientific goals and address complex project demands.
Push the boundaries of protein science capabilities by evaluating and integrating emerging technologies to increase throughput, data quality, and platform efficiency.

Direct and optimize protein production from a range of host organisms (E. coli, cell-free, and mammalian), and a range of throughputs 10 to 1000s at varying volumes.
Qualify all recombinant proteins by spectroscopic (UV, fluorescence), electrophoresis (SDS-PAGE), aggregation (analytical SEC), validated interactions (BLI/SPR), and identity (MS) methods.
Characterize antibodies for therapeutic properties such as binding kinetics, epitope, stability (thermal and pH), polyspecificity, aggregation propensity, etc..
Direct the purification of soluble and membrane proteins using AKTA (and other) purification systems.
Utilize automation systems to ensure efficient and precise execution of experiments.

Collaborate with Process Development to strategize and perform critical experiments required for clinical development. Able to translate research assays to validated assays for the CMC process.
Train and mentor junior team members, providing guidance on experimental design, data analysis, and troubleshooting.
Maintain accurate and detailed records of experiments, protocols, and results in accordance with company standards and regulatory requirements.
Interpret and present scientific findings at research meetings. Provide scientific input and propose follow-up experiments.
Contribute to scientific publications, patents, and presentations to disseminate research findings both internally and externally.

Qualifications

B.S. or Ph.D in Structural Biology, Protein Biochemistry, or related fields with 10+ years of industrial experience.
Deep experience in designing and optimizing antibody production processes, including fermentation, cell culture, and purification.
Experience in using automation to generate high throughput (1000+) small-scale antibodies and related molecules.
Hands-on experience in utilizing a variety of analytical techniques like HPLC, Mass Spectrometry, BLI, SPR, ELISA, and CE-SDS for antibody characterization.
Analyzing experimental data, drawing conclusions, and providing insights to inform process optimization
Working with cross-functional teams, including research, CMC, and clinical, to ensure alignment and successful product development.
Maintaining detailed documentation of experimental designs, methods, and results in electronic lab notebooks. You are conscientious, detail-oriented, and organized.
Contributing to the preparation of technical reports and regulatory documentation.
Training and mentoring junior team members in protein production and analytical techniques.

Nice to have Skill(s)

Background in structural biology (X-ray crystallography or cryo-EM) is highly desirable.
Experience using LIMS and Benchling systems.

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 $196,000 - $245,000 annually; however, the base pay offered will 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.