Expansins

Fleming AJ, McQueen-Mason S, Mandel T, Kuhleimer C. Induction of leaf pri-mordia by the cell wall protein expansin. Science 1997 276 1415-1417. 

Kalamaki, M.S., Harpster, M.H., Palys, J.M., Labavitch, J.M., Reid, D.S., Brummell, DA. (2003). Transgenic overexpression of expansin influences particle size distribution and improves viscosity of tomato juice and paste. J. Agric. FoodChem. 51, 7456-7464. 

One strategy to the enhance CO2 fixation in woody plants is to enhance the expression of genes required for cellulose deposition, which should enhance plant growth either by cell wall or just cellulose deposition. We have already isolated the full length of cDNAs for three kinds of cellulases, XET and expansin as plant cell growth regulators, and for two kinds of cellulose synthases and suCTOse synthase as a system of cellulose synthesis, as summarized in Table 2. If cellulose deposition is increased by the increased activity of each enzyme in the transformants of Arabidopsis, the gene can be introduced to woody plants to determine the cellulose deposition. 

In addition, a new class of proteins (a-expansins) has been discovered in plants that appear to disrupt the interactions between cellulose chains, without hydrolytic activity, to allow cell wall expansion [18]. A different, but related, set of molecules (P-expansins) has been found in pollen [19]. These molecules appear to help the growing pollen tube penetrate through the cell walls in the ovule allowing fertihzation. There is prehminary evidence that the addition of expansin to cellulases stimulates crystalhne cellulose hydrolysis [20]. 

Patulin 4-hydroxy-4//-furo[3,2-c]pyran-2(6//)-one, claviformin, expansin. ... 

MBHA, and (Met)Expansin (60) resins with an amide linkage. The model tripeptide aldehyde Boc-Phe-Val-Ala-H was synthesized on the three resins. These peptides were checked by RP-HPLC and studied by NMR in CDCI3 without purification. The results showed that peptide aldehydes with high purity could be obtained using this strategy with no detectable trace of racemization (within the limit of sensitivity of NMR). 

Figure 6. The potential sites for modification of Type I primary cell walls by enzymes and/or expansins. The activities of the enzymes/expansins are associated with numerous aspects of plant growth and development including cell expansion, fruit ripening, and organ abscission.

D.J. Cosgrove. Cell wall loosening by expansins. Plant Physiol, 1998,118, 333-339 A.J. Fleming, S. McQueen-Mason, T. Mandel, C. Kuhlemeier. Induction of leaf primordia by the cell-wall protein expansin. Science, 1997, 276, 1415-1418... 

D. Reinhardt, F. Wittwer, T. Mandel, C. Kuhlemeier. Localized uprcgulation of a new expansin gene predicts the site of leaf formation in the tomato meristem. Plant Cell, 1998, 10, 1427-1437... 

J.K.C. Rose, H.H Lee, A.B. Bennett. Expression of a divergent expansin gene is fruit-specific and ripening-regulated. Proc Natl Acad Sci USA, 1997, 94, 5955 5960... 

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