کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1943065 | 1052644 | 2009 | 8 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Remodeling of tobacco thylakoids by over-expression of maize plastidial transglutaminase Remodeling of tobacco thylakoids by over-expression of maize plastidial transglutaminase](/preview/png/1943065.png)
Transglutaminases (TGases, EC 2.3.2.13) are intra- and extra-cellular enzymes that catalyze post-translational modification of proteins by establishing ɛ-(γ-glutamyl) links and covalent conjugation of polyamines. In chloroplast it is well established that TGases specifically polyaminylate the light-harvesting antenna of Photosystem (PS) II (LHCII, CP29, CP26, CP24) and therefore a role in photosynthesis has been hypothesised (Della Mea et al. [23] and refs therein). However, the role of TGases in chloroplast is not yet fully understood. Here we report the effect of the over-expression of maize (Zea mays) chloroplast TGase in tobacco (Nicotiana tabacum var. Petit Havana) chloroplasts. The transglutaminase activity in over-expressers was increased 4 times in comparison to the wild-type tobacco plants, which in turn increased the thylakoid associated polyamines about 90%. Functional comparison between Wt tobacco and tgz over-expressers is shown in terms of fast fluorescence induction kinetics, non-photochemical quenching of the singlet excited state of chlorophyll a and antenna heterogeneity of PSII. Both in vivo probing and electron microscopy studies verified thylakoid remodeling. PSII antenna heterogeneity in vivo changes in the over-expressers to a great extent, with an increase of the centers located in grana-appressed regions (PSIIα) at the expense of centers located mainly in stroma thylakoids (PSIIβ). A major increase in the granum size (i.e. increase of the number of stacked layers) with a concomitant decrease of stroma thylakoids is reported for the TGase over-expressers.
Journal: Biochimica et Biophysica Acta (BBA) - Bioenergetics - Volume 1787, Issue 10, October 2009, Pages 1215–1222