Senior Scientist, Protein Engineering (Phage Display)

Job Description

Job DescriptionJanux Therapeutics is seeking a highly skilled Senior Scientist in Protein Engineering to advance our innovative discovery programs. This role requires hands-on expertise with phage display platforms and antibody discovery and optimization techniques, molecular cloning, library design and construction, DNA sequencing, and cell-based expression systems. As a key member of our R&D team, reporting to our Director of Research, you will work independently and collaboratively in a fast-paced biotech environment to deliver high-quality results under tight timelines. ESSENTIAL FUNCTIONS AND RESPONSIBILITIES

• Design, construct, and quality check phage display libraries used in peptide and antibody-based screening campaigns targeting diverse antigens.
• Screen synthetic and immune phage libraries for high-affinity binders.
• Characterize peptide and antibody candidates using biochemical, biophysical, and cell-based assays (e.g., ELISA, BLI, flow cytometry).
• Develop directed evolution libraries and execute screening methods to optimize peptide and antibody formats for improved affinity, stability, and developability.
• Collaborate with protein sciences and protein engineering teams to produce and validate peptide and antibody candidates.
• Analyze sequencing data from phage pools and selected clones to identify lead candidates.
• Maintain accurate and detailed experimental records and present findings in internal meetings.
• Contribute to patent filings, publications, and regulatory documentation as needed.
• Mentor junior scientists and contribute to a culture of scientific excellence and innovation.
• Perform other duties as assigned.

REQUIRED EDUCATION, EXPERIENCE, SKILLS, AND ABILITIES

• Ph.D. in Molecular Biology, Biochemistry, Immunology, or related field with 2+ years of relevant industry or postdoctoral experience (or M.S. with 5+ years at Scientist level).
• Hands-on experience with phage display platforms and antibody selection techniques.
• Strong understanding of antibody structure-function relationships and engineering strategies.
• Proficiency in molecular cloning, library construction, sequencing, and cell-based expression systems (bacterial, yeast, mammalian).
• Experience with analytical tools such as ELISA, liquid handler automation, plate-based assays, flow cytometry, and affinity measurements (SPR, BLI).
• Excellent problem-solving skills and ability to work independently and collaboratively.
• Highly proficient with Excel and molecular biology software (e.g. Geneious).

PREFERRED EXPERIENCE, SKILLS, AND ABILITIES

• Experience with next-generation sequencing (NGS) analysis of phage libraries.
• Familiarity with other display technologies (e.g., yeast, mammalian, p-display).
• Knowledge of developability profiling (stability, post translational modifications, immunogenicity).
• Prior experience in therapeutic antibody development or biologics pipeline.
• Experience with 3D modeling software.

In addition to a competitive base salary ranging from $144,000 to $153,000, we offer stock options, restricted stock units, a stock purchase plan (ESPP) and a target bonus. Janux also provides a comprehensive benefits package for our employees and their families, which includes medical, dental, vision, and supplemental disability insurance. Relocation assistance may also be available.Please note that the hourly rate range is a guideline, and individual total compensation will vary based on factors such as qualifications, skill level, competencies, and internal equity.Job Type: Full-time Benefits:· 401K· Medical insurance· Dental insurance· Vision insurance· Supplemental disability insurance plans· Flexible schedule· Life insurance· Flexible vacation· Sick time· Incentive stock option plan· Relocation assistance Schedule:· Monday to Friday Work authorization:· United States (Required) Additional Compensation:· Annual targeted bonus % Work Location:· On site (San Diego, CA) EQUAL OPPORTUNITY EMPLOYER:Janux Therapeutics, Inc. is an equal opportunity employer that is committed to providing a work environment free of harassment and discrimination based upon a protected category, as well as an environment free from retaliation for protected activity.

Notice to Recruiters and Third-Party AgenciesThe Talent Acquisition team manages the recruitment and employment process for Janux. To protect the interests of all parties involved, Janux will only accept resumes from a recruiter once a fully-executed search agreement is in place. Agencies are hereby specifically directed not to contact Janux employees directly in an attempt to present candidates. Janux will consider any candidate for whom an Agency and/or Recruiter has submitted an unsolicited resume to have been referred, free of any charges or fees.

We may use artificial intelligence (AI) tools to support parts of the hiring process, such as reviewing applications, analyzing resumes, or assessing responses. These tools assist our recruitment team but do not replace human judgment. Final hiring decisions are ultimately made by humans. If you would like more information about how your data is processed, please contact us.