Xin Sun

Abiologics, Inc. is a privately held, early-stage biotechnology company on a mission to make biology better through chemistry. We are pioneering the development of a transformational new class of medicines that is unlocked by novel synthetic and computational technologies.

• Built out RNA-small molecule biophysics, biochemistry and screening at an early-stage Series A company • Led programs and multi-disciplinary teams across the company’s different platform modalities to identify and advance small molecule modulators of RNA biology • Managed external collaborations to execute RNA-small molecule HTS campaigns and biophysics • Designed, developed and executed novel biochemical and biophysical assays for RNA induced-proximity, degradation and covalent modification • Led and managed protein sciences activities including recombinant protein production and structure determination by x-ray crystallography • Established and led program working groups and set clear execution strategies, deliverables and timelines to deliver on project and company goals • Led build-out of internal laboratory and screening capabilities including purchase of new equipment and automation to enable novel assay platforms and workflows • Managed a team of Scientist-and Research Associate-level direct reports and matrix-managed cross-functional junior team members

• Built a team to establish biochemical, biophysical, and cell-based screening at an early-stage Series A company to support small molecule and antibody discovery programs for kidney disease • Established internal biologics biophysics (BLI) capabilities for screening and affinity maturation • Managed external collaborations and led internal team to provide screening and pharmacology sample analysis to drive programs • Managed protein sciences efforts including recombinant protein production and characterization • Developed novel biochemical and biophysical assays to characterize small molecule-induced protein oligomerization/assembly • Managed a team of Scientist- and Research Associate-level direct reports

• Led the Screening and Biochemistry group and established standardized, semi-automated screening workflows with rigorous sample management/tracking and data analysis/reporting to drive stapled-peptide discovery programs • Led biochemical (FP, TR-FRET, Alpha) and biophysical (SPR) screening efforts to drive programs • Designed and developed biochemical assays and a screening cascade to support the targeted protein degradation platform • Led cross-functional teams to drive towards company goals • Managed a team of Scientist- and Research Associate-level scientists

• Lead biochemist in an integrated Early Discovery team with extensive collaboration with the cell assay, DEL and structural biology groups • Developed novel biochemical assays for diverse target classes (DUBs, E3 ligases, methyl transferases, kinases, and more) and led internal HTS campaigns (500K library, 10+ campaigns/year) through all phases of HTS • Extensive experience with laboratory automation (HighRes systems, Cellario software, Labcyte Echo, liquid handlers, and more) and integrating automated assay workflows • Oversaw routine screening assays supporting Hit-to-Lead and Lead Optimization programs • Designed and executed biochemical assays to investigate inhibitor mechanism of action, reversibility, and residence time to characterize lead molecules and drive SAR • Collaborated with biology and cell-based assay teams to develop protein quantitation assays (western blot, MSD) • Oversaw external collaboration to design and generate high quality protein reagents for biochemical, biophysical, structural, and DEL studies • Managed a team of Research Associate-level direct reports

Biochemist/Enzymologist in the Discovery Bioassays group responsible for designing, developing, and optimizing biochemical assays for screening. • Experience in a wide variety of biochemical assay platforms including fluorescence, HTRF, AlphaLISA, MSD, and more. • Experience with a number of target classes including kinases, pseudo kinases, proteases, E3 ligases, and more. Collaborated closely with Protein Science partners on difficult to produce targets and protein complexes. • Responsible for managing HTS campaigns at external CROs (Evotec, Charles River Laboratories). Responsibilities included in-house assay design, development and qualification, assay transfer, leading weekly teleconferences, and coordinating activities with Chemistry and Biology partners. • Expertise in studying inhibitor mechanism of action and binding modes. • Experience in biophysical techniques including SPR. • Responsible for running weekly assays to support routine screening campaigns. • Experience managing an Associate Scientist direct report.

Radical SAM superfamily enzymes catalyze chemically diverse and difficult reactions but their chemical mechanisms remain elusive. My research aimed to unravel the novel biochemistry catalyzed by MoeK5, the cobalamin-dependent radical SAM methyltransferase from the Moenomycin biosynthetic pathway. Iron-sulfur clusters are important protein cofactors but the biochemistry of how they are inserted into target proteins is poorly understood. My work aimed to develop novel chemical biology tools and assays to study iron-sulfur cluster biogenesis and trafficking in vitro.

Cryptosporidium parvum is a human parasite which causes cryptosporidiosis, for which no treatments are currently available. My research focused on characterizing a nucleotide salvage pathway enzyme, thymidine kinase, from C. parvum and studying its potential as a drug target and prodrug activator. I found that C. parvum thymidine kinase efficiently activates trifluorothymidine, an old anti-cancer drug, which showed anti-parasitic activity in a cell model of disease. Penicillium brevicompactum produces an antifungal natural product called mycophenolic acid (MPA), a potent inhibitor of the enzyme IMP dehydrogenase (IMPDH). How P. brevicompactum is able to produce this molecule and escape inhibition of its own enzyme was unknown. My work revealed that P. brevicompactum's own IMPDH is incredibly resistant to MPA and resistance results from a change in the enzyme kinetic mechanism.