MCB Faculty

Xiaojiang Chen

Professor of Biological Sciences and Chemistry

Contact Information
Phone: (213) 740-5487
Office: RRI 119A

Detailed Lab Website


  • B.S. , Shihezi University, China
  • Ph.D. Biochemistry and Molecular Biology, Virology, University of California, Davis, 7/1992

  • Postdoctoral Training

    • Postdoctoral Fellow, Harvard University, 1994-1999  

    Academic Appointment, Affiliation, and Employment History

    • Full Professor, University of Southern California, 2006-  
    • Associate Professor, University of Southern California, 2004-2006  
    • Associate Professor, University of Colorado School of Medicine, 2003-2004  
    • Assistant Professor, University of Colorado School of Medicine, 1999-2003  

    Description of Research

    Summary Statement of Research Interests
    Dr. Xiaojiang Chen's combined expertise in biochemistry, molecular and structural biology (X-ray) enables him to study important questions in Cancer Biology and Immunology at molecular/cellular levels. He has done landmark work on tumor viruses (HPV, SV40, EBV) and oncogenes, as well as important DNA modifying enzymes (the ring-shaped helicases and APOBEC mutases), which are critical to genomic stability, cancer, and immunity. His current studies focus on the following areas: [1] Cancer biology, with emphasis on cell growth regulation through oncogenes, tumor suppressors, and DNA/RNA modifying enzymes (deaminases, helicases, polymerases); [2] Immune regulation (B, T cells) and host innate/acquired humoral responses (APOBEC3s, AID, CR2/C3d) against viral infection by HIV, HPV and HCV. [3] Structure-based drug design using the atomic structures of cancer-promoting protein targets, in order to develop molecular probes for studying cancer biology, as well as for potential lead candidates for cancer therapy.
    Research Keywords
    Cancer; Immunity; Oncogenes, Tumor suppressor, DNA modifying enzymes; Molecular motors; Helicases; APOBEC deaminase; Structural Biology, X-ray Crystallography
    Research Specialties
    Cancer Biology, Immunology, Virology, Biochemistry, Molecular Biology, Structural Biology, X-ray Crystallography

    Affiliations with Research Centers, Labs, and Other Institutions

    • 1) Professor XJ Chen's Lab, Head,
    • 2) Chemistry Department, Professor,
    • 3) Program in Biomedical, Biol Sciences, Member, Professor,
    • 4) Centr of Excellence in NanoBiophysics, Director,
    • 5) Norris Cancer Centr, Member, Professor


    Journal Article
    • Fu, Y., Slaymaker, I. M., Wang, J., Wang, G., Chen,Fu, X. S., Slaymaker, I. M., Wang, J., Wang, G., Chen, X. S. (2014). The 1.8-Å crystal structure of the N-terminal domain of an archaeal MCM as a right-handed filament. J.M.B. (426:7), pp. 1512-23. PubMed Web Address
    • Chang, Y. P., Xu, M., Machado, A. C., Yu, X. J., Rohs, R., Chen, X. S. (2013). Mechanism of origin DNA recognition and assembly of an initiator-helicase complex by SV40 large tumor antigen. Cell reports. Vol. 3 (4), pp. 1117-27. PubMed Web Address
    • Patrick, A. N., Cabrera, J. H., Smith, A. L., Chen, X. S., Ford, H. L., Zhao, R. (2013). Structure-function analyses of the human SIX1-EYA2 complex reveal insights into metastasis and BOR syndrome. Nature structural & molecular biology. Vol. 20 (4), pp. 447-53. PubMed Web Address
    • Slaymaker, I. M., Fu, Y., Toso, D. B., Ranatunga, N., Brewster, A., Forsburg, S. L., Zhou, Z. H., Chen, X. S. (2013). Mini-chromosome maintenance complexes form a filament to remodel DNA structure and topology. Nucleic acids research. Vol. 41 (5), pp. 3446-56. PubMed Web Address
    • Asokan, R., Banda, N. K., Szakonyi, G., Chen, X. S., Holers, V. M. (2013). Human complement receptor 2 (CR2/CD21) as a receptor for DNA: implications for its roles in the immune response and the pathogenesis of systemic lupus erythematosus (SLE). Molecular immunology. Vol. 53 (1-2), pp. 99-110. PubMed Web Address
    • Wang, W., Nie, J., Prochnow, C., Truong, C., Jia, Z., Wang, S., Chen, X. S., Wang, Y. (2013). A systematic study of the N-glycosylation sites of HIV-1 envelope protein on infectivity and antibody-mediated neutralization. Retrovirology. Vol. 10, pp. 14. PubMed Web Address
    • Gai, D., Chang, Y. P., Chen, X. S. (2010). Origin DNA melting and unwinding in DNA replication. Current opinion in structural biology. Vol. 20 (6), pp. 756-62. PubMed Web Address
    • Brewster, A. S., Chen, X. S. (2010). Insights into the MCM functional mechanism: lessons learned from the archaeal MCM complex. Critical reviews in biochemistry and molecular biology. Vol. 45 (3), pp. 243-56. PubMed Web Address
    • Shi, Y., Liu, H., Gai, D., Ma, J., Chen, X. S. (2009). A computational analysis of ATP binding of SV40 large tumor antigen helicase motor. PLoS computational biology. Vol. 5 (9), pp. e1000514. PubMed Web Address
    • Liu, H., Shi, Y., Chen, X. S., Warshel, A. (2009). Simulating the electrostatic guidance of the vectorial translocations in hexameric helicases and translocases. Proceedings of the National Academy of Sciences of the United States of America. Vol. 106 (18), pp. 7449-54. PubMed Web Address
    • Chiang, A. N., Valderramos, J. C., Balachandran, R., Chovatiya, R. J., Mead, B. P., Schneider, C., Bell, S. L., Klein, M. G., Huryn, D. M., Chen, X. S., Day, B. W., Fidock, D. A., Wipf, P., Brodsky, J. L. (2009). Select pyrimidinones inhibit the propagation of the malarial parasite, Plasmodium falciparum. Bioorganic & medicinal chemistry. Vol. 17 (4), pp. 1527-33. PubMed Web Address
    • Brewster, A. S., Wang, G., Yu, X., Greenleaf, W. B., Carazo, J. M., Tjajadi, M., Klein, M. G., Chen, X. S. (2008). Crystal structure of a near-full-length archaeal MCM: functional insights for an AAA+ hexameric helicase. Proceedings of the National Academy of Sciences of the United States of America. Vol. 105 (51), pp. 20191-6. PubMed Web Address
    • Holden, L. G., Prochnow, C., Chang, Y. P., Bransteitter, R., Chelico, L., Sen, U., Stevens, R. C., Goodman, M. F., Chen, X. S. (2008). Crystal structure of the anti-viral APOBEC3G catalytic domain and functional implications. Nature. Vol. 456 (7218), pp. 121-4. PubMed Web Address
    • Wang, G., Klein, M. G., Tokonzaba, E., Zhang, Y., Holden, L. G., Chen, X. S. (2008). The structure of a DnaB-family replicative helicase and its interactions with primase. Nature structural & molecular biology. Vol. 15 (1), pp. 94-100. PubMed Web Address
    • Chang, Y. P., Wang, G., Bermudez, V., Hurwitz, J., Chen, X. S. (2007). Crystal structure of the GINS complex and functional insights into its role in DNA replication. Proceedings of the National Academy of Sciences of the United States of America. Vol. 104 (31), pp. 12685-90. PubMed Web Address
    • Prochnow, C., Bransteitter, R., Klein, M. G., Goodman, M. F., Chen, X. S. (2007). The APOBEC-2 crystal structure and functional implications for the deaminase AID. Nature. Vol. 445 (7126), pp. 447-51. PubMed Web Address
    • Bishop, B., Dasgupta, J., Chen, X. S. (2007). Structure-based engineering of papillomavirus major capsid l1: controlling particle assembly. Virology journal. Vol. 4, pp. 3. PubMed Web Address
    • Szakonyi, G., Klein, M. G., Hannan, J. P., Young, K. A., Ma, R. Z., Asokan, R., Holers, V. M., Chen, X. S. (2006). Structure of the Epstein-Barr virus major envelope glycoprotein. Nature structural & molecular biology. Vol. 13 (11), pp. 996-1001. PubMed Web Address
    • Lilyestrom, W., Klein, M. G., Zhang, R., Joachimiak, A., Chen, X. S. (2006). Crystal structure of SV40 large T-antigen bound to p53: interplay between a viral oncoprotein and a cellular tumor suppressor. Genes & development. Vol. 20 (17), pp. 2373-82. PubMed Web Address
    • Shen, J., Gai, D., Patrick, A., Greenleaf, W. B., Chen, X. S. (2005). The roles of the residues on the channel beta-hairpin and loop structures of simian virus 40 hexameric helicase. Proceedings of the National Academy of Sciences of the United States of America. Vol. 102 (32), pp. 11248-53. PubMed Web Address
    • Gai, D., Zhao, R., Li, D., Finkielstein, C. V., Chen, X. S. (2004). Mechanisms of conformational change for a replicative hexameric helicase of SV40 large tumor antigen. Cell. Vol. 119 (1), pp. 47-60. PubMed Web Address
    • Bemis, L., Chan, D. A., Finkielstein, C. V., Qi, L., Sutphin, P. D., Chen, X., Stenmark, K., Giaccia, A. J., Zundel, W. (2004). Distinct aerobic and hypoxic mechanisms of HIF-alpha regulation by CSN5. Genes & development. Vol. 18 (7), pp. 739-44. PubMed Web Address
    • Gomez-Lorenzo, M. G., Valle, M., Frank, J., Gruss, C., Sorzano, C. O., Chen, X. S., Donate, L. E., Carazo, J. M. (2003). Large T antigen on the simian virus 40 origin of replication: a 3D snapshot prior to DNA replication. The EMBO journal. Vol. 22 (23), pp. 6205-13. PubMed Web Address
    • Li, D., Zhao, R., Lilyestrom, W., Gai, D., Zhang, R., DeCaprio, J. A., Fanning, E., Jochimiak, A., Szakonyi, G., Chen, X. S. (2003). Structure of the replicative helicase of the oncoprotein SV40 large tumour antigen. Nature. Vol. 423 (6939), pp. 512-8. PubMed Web Address
    • Fletcher, R. J., Bishop, B. E., Leon, R. P., Sclafani, R. A., Ogata, C. M., Chen, X. S. (2003). The structure and function of MCM from archaeal M. Thermoautotrophicum. Nature structural biology. Vol. 10 (3), pp. 160-7. PubMed Web Address
    • Chen, X. (2002). Boackle S., Holers M., Chen X., Szakonyi G., Karp D, Wakeland E and Morel L. Cr2, a candidate gene in the NZM2410 Sle1c lupus susceptibility locus, encodes a dysfunctional protein. IMMUNITY, (2001) 15, 729-738.
    • Chen, X. (2001). Szakonyi G, Guthridge J, Li D, Young K, Holers M, Chen X. Structure of Complement Receptor Type 2 in Complex with Its Ligand C3d. SCIENCE. (2001) 292, 1725-1728.
    • Chen, X. (2000). Chen X, Garcea R, Goldberg I, Casini G, Harrison C. Crystal Structure of Human Papilloma Virus T1 Particles of the Major Capsid L1 MOL. CELL. (2000) 5, 557-567.

    Honors and Awards

    • Innovative Developmental Exploratory Awards, California HIV/AIDS foundation, 2008-2010  
    • American Cancer Society Foundation Award, 2002-2003   
    • Basil O’Connor Scholar Research Award, 2002-2003   
    • Howard Hughes Medical Institute Junior Faculty Start-Up Award, 2000-2001  
    • Howard Hughes Medical Institute Postdoctoral Fellowship, 1994-1998  
    • University of California Tom-Shell Award for Outstanding Dissertation, 1992  
    • University of California Regents graduate fellowship, 1989-1991  
    • Jastro-Shields student research scholarship, 1989-1990   

    Service to the University

    Administrative Appointments
    • Director for Center of Excellence in NanoBiophysics, 2006-2013  

  • Department of Biological Sciences
  • University of Southern California
  • Allan Hancock Foundation Building
  • Los Angeles, CA 90089-0371