| Research Interests
We use X-ray crystallography as a tool to carry out the structural biology study of various biomacromolecules. Meanwhile, we perform the biological functional study of proteins by biochemical and biophysical methods, such as Sedimentation (Analytical Ultracentrifuge), CD (Circular dichroism), HPLC (High Performance Liquid Chromatography), ITC (Isothermal Titration Calorimetry), and SPR (Surface Plasmon Resonance) etc. The bioinfomatics and the three dimensional structure of target proteins are applied in structure based drug design. Our laboratory mainly focus in structural and functional studies of (1) A proton pumping protein: H+-translocating pyrophosphatase (2) Polyamine biosynthesis enzymes from Helicobacter pylori, (3) Virulence factors from pathogenic Leptospira.
(1) Structural and functional studies of a membrane-embedded H+-translocating pyrophosphatase
氫離子通道膜蛋白焦磷酸水解西每的結構與功能之研究
H+-translocating pyrophosphatases (H+-PPases) are active proton transporters that generate a proton gradient across the endomembrane by means of pyrophosphate (PPi) hydrolysis. H+-PPases are found primarily in the vacuolar membrane of plants and the plasma membrane of several protozoa and prokaryotes. We determined the crystal structure of a Vigna radiata H+-PPase (VrH+-PPase) in complex with a non-hydrolysable substrate analogue, imidodiphosphate (IDP), at 2.35? resolution. VrH+-PPase comprises an integral membrane domain formed by 16 transmembrane helices. A novel proton translocation pathway is created by six core transmembrane helices. We proposed a working model of the mechanism for the coupling between proton pumping and PPi hydrolysis by H+-PPases.
(2) Structural and functional studies of polyamine biosynthesis enzymes from Helicobacter pylori
胃幽門螺桿菌中多胺生物合成西每的結構與功能之研究
Polyamines (putrescine, spermidine, and spermine) are essential for cell growth in a number of organisms and have been implicated in the regulation of a wide variety of physiological functions. The synthesis, metabolism, uptake and function of polyamine can be used as targets for cancer prevention and therapy. These polyamine biosynthesis enzymes exhibit features that differ with the human host therefore they can be as drug targets. The crystal structure of spermidine synthase from H. pylori (HpPAPT) has been determined in our laboratory. Three additional genes of polyamine biosynthesis enzymes, diaminopimelate decarboxylase (DAPDC), arginine decarboxylase (ADC), and arginase, are under study. The investigation of polyamine biosynthesis enzymes and its potent inhibitors also are ongoing.
(3) Structural and functional studies of virulence factors from pathogenic Leptospira
鉤端螺旋體毒素蛋白的結構與功能之研究
Leptospirosis is a prevalent infectious disease affecting both humans and animals worldwide. Kidney is the main target of Leptospira in both acute and chronic infections. Tubulointerstitial nephritis is a cardinal renal manifestation caused by pathogen Leptospira that most accumulate in the proximal tubules. The potent virulence factors related to leptospirosis renal disease includs lipoproteins-LipL32 and LipL41; immunoglobulin-like proteins-LigA, LigB and LigC; OmpA-like protein Loa22, laminin- binding and fibronectin-binding proteins-LenA/B/C/D/E/F etc.,. LipL32 is the most important virulence factor from Leptospira. LipL32 evades immune response by recognizing and adhering to extracellular matrix components of the host cell. The three dimensional structure of LipL32 has been determined in our laboratory. LipL32 reveals Ca2+ and fibronectin binding activities. Try to understand the possible mechanism of nephritis disease in leptospirosis from the structure and functional study of the virulence factors.
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