Research Interests

My long-term research goals are to develop Bacillus subtilis, a gram-positive bacterium, as a microbial factory to produce biotechnologically important proteins via secretion and to design/produce interesting proteins in their natural and engineered forms. To develop the B. subtilis expression (secretion and surface display) systems, I have focused my research to four key areas:

(1) Regulation of gene expression. Glucitol induction mechanism is selected as a model system with the focus to study the structure and function of an ATP-dependent transcription activator protein, GutR.

(2) Cell surface display system. Engineering of cell wall protein for functional surface display of enzymes and enzyme complexes.

(3) Studies of molecular chaperon operons. Structural genes encoding B. subtilis GroES and GroEL were cloned and overexpressed to study the molecular chaperone mediate protein folding in vitro and in vivo.

(4) Extracellular proteases. Isolation and inactivation of chromosomal genes encoding extracellular proteases that degrade secreted proteins. This leads to the development of extracellular protease deficient strains for expression studies.

While the development and improvement of the secretion and surface display systems are in progress, several interesting proteins including single-chain antibodies, bacterial plasminogen activators (blood-clot dissolving agents) and streptavidin are selected to evaluate the effectiveness of this expression system. Certain novel and desirable properties will be introduced into these molecules through genetic and protein engineering.

 

Courses Taught

Graduate Students

Selected publications

• 1. Wu, S. C., K. K. Ng, and S. -L. Wong. 2009. Engineering monomeric streptavidin and its ligands with infinite affinity in binding but reversibility in interaction. Proteins 77:404-412.
  

• 2. Chen, C.-L., S.-C. Wu, W.-T. Tjia, C.L.C. Wang, M. J. Lohka and S.-L Wong. 2008.  Development of a LytE-based high-density surface display system in Bacillus subtilis. Microbial Biotechnology. 1:177-190.
  

• 3. Arai, T., S. Matsuoka, H.-Y. Cho, H. Y. M. Inui, S.-L Wong and R. H. Doi. 2007.Synthesis of Clostridium cellulovorans minicellulosomes by intercellular complementation.  Proc. Natl. Acad. Sci. U. S. A. 104:1456-1460.
  

• 4. Wu, S.-C. and S.-L. Wong. 2006. Intracellular production of a soluble and functional monomeric streptavidin in Escherichia coli and its application for affinity purification of biotinylated proteins. Protein Expr.Purif. 46:268-273
  

• 5. Wu, S.-C. and S.-L. Wong. 2005. Engineering soluble monomeric streptavidin with reversible biotin binding capability. J.Biol.Chem. 280:23225-23231
  

• 6. Wu, S.-C. and S.-L. Wong. 2004. Development of an enzymatic method for site-specific incorporation of desthiobiotin to recombinant proteins in vitro. Anal.Biochem. 331:340-348
  

• 7. Cho, H. Y., H. Yukawa, M. Inui, R. H. Doi, and S.-L. Wong. 2004. Production of Minicellulosomes from Clostridium cellulovorans in Bacillus subtilis WB800. Appl.Environ.Microbiol. 70:5704-5707
  

• 8. Wu, S. -C., F. J. Castellino, and S.-L. Wong. 2003. A Fast-acting, Modular-structured Staphylokinase Fusion with Kringle-1 from Human Plasminogen as the Fibrin-targeting Domain Offers Improved Clot Lysis Efficacy. J.Biol.Chem. 278:18199-18206
  

• 9. Lian, Q., S. J. Szarka, K. K. Ng, and S.-L. Wong. 2003. Engineering of a staphylokinase-based fibrinolytic agent with antithrombotic activity and targeting capability towards thrombin-rich fibrin and plasma clots. J.Biol.Chem. 278:26677-26686
  

• 10. Wu, S.-C., J. C. Yeung, Y. Duan, R. Ye, S. J. Szarka, H. R. Habibi, and S.-L. Wong. 2002. Functional Production and Characterization of a Fibrin-Specific Single-Chain Antibody Fragment from Bacillus subtilis: Effects of Molecular Chaperones and a Wall-Bound Protease on Antibody Fragment Production. Appl.Environ.Microbiol. 68:3261-3269
  

• 11. Wu, S.-C. and S.-L. Wong. 2002. Engineering of a Bacillus subtilis Strain with Adjustable Levels of Intracellular Biotin for Secretory Production of Functional Streptavidin. Appl.Environ.Microbiol. 68:1102-1108