Bombyx mori fibroin

Normal transmission IRLD can also be used to characterize polymeric fibers, although scattering can induce sloping baselines. Raman spectroscopy then becomes a convenient alternative. Rutledge et al. have recently probed the orientation in electrospun nanofibers composed of a core of Bombyx mori fibroin and an outer shell of poly (ethylene oxide) [24], The orientation values were low, less than 0.1, as is often the case in electrospun fibers. 

Zhou, C.-Z., Confalonieri, F., Medina, N., Zivanovic, Y., Esnault, C., Yang, T.,Jacquet, M., Janin.J., Duguet, M., Perasso, R., and Li, Z.-G. (2000). Fine organization of Bombyx mori fibroin heavy chain gene. Nucleic Acids Research 28(12), 2413-2419. 

Ribonucieic acid (Bombyx mori fibroin-specifying messenger) 429b, 3126a, 4249... 

A detailed structure for Tussah silk fibroin has been derived which is in agreement with the X-ray diffraction data. The structure is similar to that of Bombyx mori fibroin in that it is based on anti-parallel-ohain pleated sheets the method of packing of the sheets, however, is quite different. 

Trabbic, K.A., Yager, P., 1998. Comparative structural characterization of naturally- and synthetically-spun fibers of Bombyx mori fibroin. Macromolecules 31 (2), 462—471. 

H. Saito, R. Tabeta, T. Asakura, Y. Iwanaga, A. Shoji, T. Ozaki, I. Ando, High-resolution C-13 NMR-study of silk fibroin in the solid-state by the cross-polarization magic angle spinning method—conformational characterization of silk-I and silk-II type forms of Bombyx mori fibroin by the conformation-dependent C-13 chemical-shifts. Macromolecules 17 (1984) 1405-1412. 

KUcuchi, Y., Mori, K., Suzuki, S., Yamaguchi, K. and Mizuno, S., Structure of the Bombyx-mori fibroin light-chain-encoding gene - Upstream sequence elements common to the light and heavy-chain. Gene, 1992, 110(2) 151-158. 

Another related paper by Zhou et al. has focused on the influence of pH and Ca ions on the conformational transition from silk I to silk II in regenerated Bombyx mori fibroin. Carbon-13 CP MAS NMR was used to quantify changes observed. 

Average wing-hinge Prealar arm Collagen (oxhide) Elastin (ox ligamentum nuchae) Silk fibroin Bombyx mori)... 

Raw silk was dissolved in hexafluoro-iso-propanol (HFIP) [17, 33]. A typical working concentration for spinning was 2.5% (w/v) silk fibroin in HFIP. The spinning solution was pressed through a small needle (0 80-250 pm) into a precipitation bath (methanol for Bombyx mori silk proteins and acetone for Nephila clavipes silk proteins) and the silk solution immediately precipitated as a fiber. The best performing fibers approached the maximum strength measured for native fibers of Bombyx mori, but did not achieve the mechanical properties of natural spider silk. 

Silk fibers or monolayers of silk proteins have a number of potential biomedical applications. Biocompatibility tests have been carried out with scaffolds of fibers or solubilized silk proteins from the silkworm Bombyx mori (for review see Ref. [38]). Some biocompatibility problems have been reported, but this was probably due to contamination with residual sericin. More recent studies with well-defined silkworm silk fibers and films suggest that the core fibroin fibers show in vivo and in vivo biocompatibility that is comparable to other biomaterials, such as polyactic acid and collagen. Altmann et al. [39] showed that a silk-fiber matrix obtained from properly processed natural silkworm fibers is a suitable material for the attachment, expansion and differentiation of adult human progenitor bone marrow stromal cells. Also, the direct inflammatory potential of silkworm silk was studied using an in vitro system [40]. The authors claimed that their silk fibers were mostly immunologically inert in short and long term culture with murine macrophage cells. 

Asakura, T., Sakaguchi, R., Demura, M., Manabe, T., Uyama, A., Ogawa, K., and Osanai, M. (1993). In vitro production of Bombyx-mori silk fibroin by organ-culture of the posterior silk glands—isotope labeling and fluorination of the silk fibroin. Biotech-nol. Bioeng. 41, 245-252. 

Ha, S. W., Gracz, H. S., Tonelli, A. E., and Hudson, S. M. (2005). Structural study of irregular amino acid sequences in the heavy chain of Bombyx mori silk fibroin. Biomacromolecules 6, 2563-2569. 

Hossain, K. S., Ochi, A., Ooyama, E., Magoshi,J., and Nemoto, N. (2003). Dynamic light scattering of native silk fibroin solution extracted from different parts of the middle division of the silk gland of the Bombyx mori silkworm. Biomacromolecules 4, 350-359. 

Inoue, S., Tanaka, K., Arisaka, F., Kimura, S., Ohtomo, K., and Mizuno, S. (2000a). Silk fibroin of Bombyx mori is secreted, assembling a high molecular mass elementary unit consisting of H-chain, L-chain, and P25, with a 6 6 1 molar ratio./. Biol. Chem. 275, 40517-40528. 

Inoue, S. I., Magoshi, J., Tanaka, T., Magoshi, Y., and Becker, M. (2000b). Atomic force microscopy Bombyx mori silk fibroin molecules and their higher order structure. /. Polym. Sci. BPolym. Phys. 38, 1436-1439. 

Kameda, T., Ohkawa, Y., Yoshizawa, K., Nakano, E., Hiraoki, T., Ulrich, A. S., and Asakura, T. (1999). Dynamics of the tyrosine side chain in Bombyx mori and Sarnia cynthia ricini silk fibroin studied by solid state H-2 NMR. Macromolecules 32, 8491-8495. 

Lazo, N. D., and Downing, D. T. (1999). Crystalline regions of Bombyx mori silk fibroin may exhibit beta-turn and beta-helix conformations. Macromolecules 32, 4700-4705. Lee, K. H. (2004). Silk sericin retards the crystallization of silk fibroin. Macromol. Rapid Commun. 25, 1792-1796. 

Monti, P., Taddei, P., Freddi, G., Asakura, T., and Tsukada, M. (2001). Raman spectroscopic characterization of Bombyx mori silk fibroin Raman spectrum of silk I. J. Raman Spectrosc. 32, 103—107. 

Taddei, P., and Monti, P. (2005). Vibrational infrared conformational studies of model peptides representing the semicrystalline domains of Bombyx mori sik fibroin. Biopolymers 78, 249-258. 

Terry, A. E., Knight, D. P., Porter, D., and Vollrath, F. (2004). PH induced changes in the rheology of silk fibroin solution from the middle division of Bombyx mori silkworm. Biomacromolecules 5, 768-772. 

Yang, Y. H., Shao, Z. Z., Chen, X., and Zhou, P. (2004). Optical spectroscopy to investigate the structure of regenerated Bombyx mori silk fibroin in solution. Biomacromolecules 5, 773-779. 

Yao, J. M., Nakazawa, Y., and Asakura, T. (2004). Structures of Bombyx mori and Samia cynthia ririni silk fibroins studied with solid-state NMR. Biomacromolecules 5, 680-688. 

Silk is produced from the spun threads from silkworms (the larvae of the moth Bombyx mori and related species). The main protein in silk, fibroin, consists of antiparallel pleated sheet structures arranged one on top of the other in numerous layers (1). Since the amino acid side chains in pleated sheets point either straight up or straight down (see p. 68), only compact side chains fit between the layers. In fact, more than 80% of fibroin consists of glycine, alanine, and serine, the three amino acids with the shortest side chains. A typical repetitive amino acid sequence is (Gly-Ala-Gly-Ala-Gly-Ser). The individual pleated sheet layers in fibroin are found to lie alternately 0.35 nm and 0.57 nm apart. In the first case, only glycine residues (R = H) are opposed to one another. The slightly greater distance of 0.57 nm results from repulsion forces between the side chains of alanine and serine residues (2). 

Demura M, Asakura T, Kuroo T. Immobilization of biocatalysts with bombyx mori silk fibroin by several kinds of physical treatment and its application to glucose sensors. Biosensors 1989, 4, 361-372. 

Figure 1 (a) the sericin (outer layer) and fibroin filaments of Bombyx mori silkworm (b) the... 

Fibroin (Bombyx mori) (ExPASy http //www.expasy.ch/) Spidroin (Nephila clavipe) (Shao et at, 2003)... 

Asakura, T., Sugino, R., Okumura, T., and Nakazawa, Y. "The role of irregular unit, GAAS, on the secondary structure of Bombyx mori silk fibroin studied with C-13 CP/MAS NMR and wide-angle X-ray scattering". Protein Sci. 11(8), 1873-1877 (2002). 

Asakura, T., Suita, K., Kameda, T., Afonin, S., and Ulrich, A.S. "Structural role of tyrosine in Bombyx mori silk fibroin, studied by solid-state NMR and molecular mechanics on a model peptide prepared as silk I and II". Magn. Reson. Chem. 42(2), 258-266 (2004). 

Gotoh, Y., Tsukada, M., and Minoura, N. "Effect of the chemical modification of the arginyl residue in Bombyx mori silk fibroin on the attachment and growth of fibroblast cells".. Biomed. Mater. Res. 39(3), 351-357 (1998). 

Ha, S.W., Park, Y.H., and Hudson, S.M. "Dissolution of Bombyx mori silk fibroin in the calcium nitrate tetrahydrate-methanol system and aspects of wet spinning of fibroin solution". 

Huang, X.T., Shao, Z.Z., and Chen, X. "Investigation on the biodegradation behavior of Bombyx mori silk and porous regenerated fibroin scaffold". Acta Chimica Sinica 65(22), 2592-2596 (2007). 

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