Browsing by Author "Lee, Kuan-Wei"

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Structure of native oligomeric Sprouty2 by electron microscopy and its property of electroconductivity
(2013-09-27)
Chen, Feng-Jung
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Lee, Kuan-Wei
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Lai, Chun-Chieh
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Lee, Sue-Ping
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Shen, Hsiao-Hsuian
Receptor tyrosine kinases (RTKs) regulate many cellular processes, and Sprouty2 (Spry2) is known as an important regulator of RTK signaling pathways. Therefore, it is worth investigating the properties of Spry2 in more detail. In this study, we found that Spry2 is able to self-assemble into oligomers with a high-affinity KD value of approximately 16 nM, as determined through BIAcore surface plasmon resonance analysis. The three-dimensional (3D) structure of Spry2 was resolved using an electron microscopy (EM) single-particle reconstruction approach, which revealed that Spry2 is donut-shaped with two lip-cover domains. Furthermore, the method of energy dispersive spectrum obtained through EM was analyzed to determine the elements carried by Spry2, and the results demonstrated that Spry2 is a silicon- and iron-containing protein. The silicon may contribute to the electroconductivity of Spry2, and this property exhibits a concentration-dependent feature. This study provides the first report of a silicon- and iron-containing protein, and its 3D structure may allow us (1) to study the potential mechanism through the signal transduction is controlled by switching the electronic transfer on or off and (2) to develop a new type of conductor or even semiconductor using biological or half-biological hybrid materials in the future. (C) 2013 Elsevier Inc. All rights reserved.
Synthesis and characterization of liquid crystalline side-chain block copolymers containing luminescent 4,4'-bis(biphenyl)fluorene pendants
(2007-10-15)
Lee, Kuan-Wei
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Lin, Hong-Cheu
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材料科學與工程學系
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Department of Materials Science and Engineering
A series of new liquid crystalline homopolymers, copolymers, and block copolymers were polymerized from styrene-macroinitiator (SMi) and methacrylates with pendent 4,4'-bis(biphenyl)fluorene (M1) and biphenyl-4-ylfluorene (M2) groups through atom transfer radical polymerization (ATRP). The number-average molecular weights (Mn) of polymers P1-P4 were 10,007, 14,852, 6,275, and 10,463 g mol-1 with polydispersity indices values of 1.21, 1.15, 1.31, and 1.22, respectively. All polymers exhibit the nematic phase. The thermal, mesogenic, and photoluminescent properties of all polymers were investigated. (c) 2007 Wiley Periodicals, Inc.
Synthesis and characterization of liquid-crystalline block copolymers with cyanoterphenyl moieties by atom transfer radical polymerization
(2006-08-01)
Lee, Kuan-Wei
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Wei, Kung-Hwa
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Lin, Hong-Cheu
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材料科學與工程學系
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Department of Materials Science and Engineering
A series of new mesomorphic block copolymers composed of different macroinitiators, including poly(ethylene oxide), polystyrene, and poly(ethylene oxide)-b-polystyrene, and polymethacrylate with a pendent cyanoterphenyl group were synthesized through atom transfer radical polymerization. The number-average molecular weights of the three diblock copolymers, determined by gel permeation chromatography, were 10,254, 9,772, and 15,632 g mol(-1), and their polydispersity indices were 1.17, 1.28, and 1.34. The mesomorphic and optical properties of all the block copolymers were investigated, and they possessed a smectic A phase with mesophasic ranges wider than 100 degrees C. Moreover, X-ray diffraction patterns provided evidence of the smectic A phase and the corresponding interdigitated packing of all the polymers. (c) 2006 Wiley Periodicals, Inc.
Synthesis and characterization of side-chain liquid crystalline homopolymers and block copolymers containing biphenyl4-ylthiophene and biphenyl-4-ylfluorene pendants
(2007-06-15)
Lee, Kuan-Wei
;
Lin, Hong-Cheu
;
材料科學與工程學系
;
Department of Materials Science and Engineering
A series of new liquid crystalline homopolymers (PI and P2) and block copolymers (P3 and P4) composed of methacrylates containing pendant biphenyl-4-ylthiophene (M1) and biphenyl-4-ylfluorene (M2) units were synthesized by atom transfer radical polymerization (ATRP). The number-average molecular weights (M-n) of the homopolymer (P2) and diblock copolymers (P3 and P4) were in the range of 5153-8713 g mol(-1) with polydispersity indices (PDIs) between 1.17 and 1.25. The thermal, mesogenic, and photoluminescence (PL) properties of all polymers were investigated. Except for the absence of mesogenic properties in block copolymer P4, polymers P1 and P3 possessed the smectic A phase and polymer P2 exhibited the nematic phase. Moreover, the mesomorphism and the layer d-spacing values of the smectic A phase in polymers P1 and P3 were confirmed and characterized by X-ray diffraction (XRD) patterns. (C) 2007 Elsevier Ltd. All rights reserved.