Scientist – Peptide Chemistry and Antibody Conjugation

Prellis Biologics is advancing next-generation antibody therapeutics by integrating machine learning, scalable biology, and proprietary 3D-printed human lymph node organoids. We are expanding our platform into complex antibody modalities to develop innovative biologic medicines, with programs spanning obesity, inflammation and immunology (I&I), and oncology.

Role Overview

We are seeking a motivated Scientist in Peptide Chemistry and Bioconjugation with strong expertise in peptide design, peptide structure–activity relationship (SAR) analysis, and peptide synthesis. The successful candidate will design and optimize peptides and develop peptide–antibody conjugates using diverse chemistries, including thiol-based coupling and bioorthogonal click chemistry. This role involves applying peptide chemistry and bioconjugation strategies to generate well-characterized conjugates and support the development of innovative targeted biologic therapeutics in a collaborative research environment.

Key Responsibilities

• Design and execute engineered cysteine antibody conjugation workflows while preserving native interchain disulfides.
• Develop and optimize peptide–antibody conjugation strategies using thiol-reactive chemistries including bromoacetyl–cysteine coupling.
• Implement controlled reduction strategies to selectively expose engineered cysteine residues.
• Optimize reaction stoichiometry, linker chemistry, and reaction conditions to improve peptide-to-antibody ratios and product homogeneity.
• Investigate and mitigate sources of conjugation heterogeneity such as over-reduction, disulfide scrambling, hydrolysis, and aggregation.
• Design peptide sequences and perform peptide structure–activity relationship (SAR) studies to optimize binding affinity, stability, and conjugation efficiency.
• Apply diverse conjugation chemistries including thiol-reactive linkers, maleimide coupling, NHS ester chemistry, and bioorthogonal click chemistry (e.g., azide–alkyne cycloaddition).
• Characterize conjugates using analytical techniques including SEC-HPLC, LC-MS (intact/reduced), RP-HPLC, and SDS-PAGE.

Qualifications

Required

• PhD in Chemistry, Chemical Biology, Biochemistry, or a closely related discipline with strong training in peptide chemistry and bioconjugation.
• Strong expertise in peptide design and peptide Structure–Activity Relationship (SAR) analysis to optimize binding, stability, and biological activity.
• Hands-on experience in peptide chemistry including solid-phase peptide synthesis (SPPS), peptide modification, purification, and analytical characterization.
• Experience in peptide–antibody conjugation using multiple chemistries, including thiol-reactive linkers, maleimide chemistry, NHS ester chemistry, and bioorthogonal click chemistry approaches (e.g., azide–alkyne cycloaddition).
• Experience with thiol-reactive peptide conjugation strategies such as bromoacetyl–cysteine chemistry or related conjugation approaches.
• Demonstrated expertise in site-specific antibody conjugation and bioconjugation chemistry.
• Experience with protein purification systems (e.g., ÄKTA).
• Expertise in analytical characterization of protein and peptide conjugates using techniques such as SEC-HPLC, LC-MS, RP-HPLC, and SDS-PAGE.
• Understanding of antibody structure, disulfide engineering, and conjugation-driven heterogeneity.

Preferred

• Experience with antibody–peptide conjugates, antibody–drug conjugates (ADCs), or targeted delivery platforms.
• Experience applying peptide SAR to optimize linker design, stability, and conjugation performance.
• Familiarity with bioorthogonal conjugation techniques and next-generation site-specific conjugation platforms.
• Experience supporting process development, scale-up, or CMC activities.

About Prellis Biologics

At Prellis we integrate human biology with machine learning. We aim to revolutionized drug discovery by harnessing the power of human immune system with tightly, integrated machine learning to develop next-generation antibody therapeutics with unparalleled speed, precision and safety. We are committed to empowering our pharmaceutical partners with access to the most promising fully human body candidate rapidly identified from the human immune repertoire, enabling them to bring life-changing treatments to patients faster than ever before.

Prellis Biologics is a pre-IPO biotech located in Berkeley CA with a team-oriented, inclusive, and family-friendly culture. Our growing pipeline target high unmet patient needs across therapeutics including metabolic, inflammation, and oncology disease. Prellis has raised funding from top investors, including Celesta, Khosla Ventures, SOSV, & Avidity Partners.

Application deadline

Prellis does not have an application deadline for this position; we will continue accepting applications until we receive a sufficient number or select a candidate for the position.

Prellis Bio is an equal opportunity employer. All applicants will be considered for employment without attention to race, color, religion, sex, sexual orientation, gender identity, national origin, veteran or disability status.

We believe diversity, equity, and inclusion need to be at the foundation of our culture. We work hard to bring together diverse teams–grounded in a wide range of expertise and life experiences–and work even harder to ensure those teams thrive in inclusive, growth-oriented environments supported by equitable company and team practices. All candidates can expect equitable treatment, respect, and fairness throughout the interview process.