Biocatalysis: We are examining the structure-function relationship of the microbial cellulosome, an extracellular cellulase complex. We have uncovered an intriguing and non-conventional cellulolytic process, which involves an anchor/scaffolding protein (CipA), which consists of a cellulose binding domain and nine repeated receptor domains.

Despite its complexity, the organization of the cellulosome follows a very simple rule: attack of the repeated and ordered structure of the substrate (cellulose) with repeated and ordered protein domains through the quaternary structure. An even simpler rule is used in organizing the quaternary structure by employing a universal set of ligands/receptors. The elegance and the beauty revealed by this model are fascinating. It represents a new concept not only for cellulose degradation, but also for supramolecular protein structure. Currently, the study employs molecular biology, protein biochemistry, and biophysical approaches, such as protein NMR to probe the detailed structures of the cellulosome.

Development of Bone Marrow Mimicry: A tissue engineering approach is taken to culture murine and human bone marrow cells in a packed-bed bioreactor providing an artificial three-dimensional scaffolding. Although the traditional flask long-term bone marrow culture (Dexter culture) gives rise only to neutrophils and monocytes-macrophages, multilineal hemopoiesis occurs in the bioreactor. The cell output includes all stages/subtypes of granulocytes, erythrocytes, monocytes-macrophages, and megakaryocytes. In addition, lymphoid cells such as T-cells, B-cells and NK cells are produced. The bone marrow bioreactor therefore provides a novel model for delineating the hemopoietic microenvironment and may be optimized for amplifying stem cells for transplantation or gene therapy.

Jindou S, Soda A, Karita S, Kajino T, Beguin P, Wu JH, Inagaki M, Kimura T, Sakka K, Ohmiya K. Cohesin-dockerin interactions within and between Clostridium josui and Clostridium thermocellum: binding selectivity between cognate dockerin and cohesin domains and species specificity. J Biol Chem. 279:9867-74, 2004.

Omasa T, Chen YG, Mantalaris A, Tsai YC, Wu JH. Molecular cloning and sequencing of the human heme-regulated eukaryotic initiation factor 2 alpha (eIF-2 alpha) kinase from bone marrow culture. DNA Seq. 13:133-7, 2002.

Lytle BL, Volkman BF, Westler WM, Heckman MP, Wu JH. Solution structure of a type I dockerin domain, a novel prokaryotic, extracellular calcium-binding domain. J Mol Biol 307:745-53, 2001.

Mantalaris A, Panoskaltsis N, Sakai Y, Bourne P, Chang C, Messing EM, Wu JH. Localization of androgen receptor expression in human bone marrow. J Pathol 193:361-6, 2001.

Waugh RE, Mantalaris A, Bauserman RG, Hwang WC, Wu JH. Membrane instability in late-stage erythropoiesis. Blood 97:1869-75, 2001.

Lytle BL, Volkman BF, Westler WM, Wu JH. Secondary structure and calcium-induced folding of the Clostridium thermocellum dockerin domain determined by NMR spectroscopy. Arch Biochem Biophys. 379:237-44, 2000.

Lytle B, Wu JH. Involvement of both dockerin subdomains in assembly of the Clostridium thermocellum cellulosome. J Bacteriol 180:6581-5, 1998.

Mantalaris A, Keng P, Bourne P, Chang AY, Wu JH. Engineering a human bone marrow model: a case study on ex vivo erythropoiesis. Biotechnol Prog 14:126-33, 1998.