大量元素鉀ppt課件-資料下載頁
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【正文】 by the concentration of cytosolic Ca2+ (150 nM) EF hand : Ca2+ binding motifs Indicating a link between Ca2+mediated signaling processes and K+ transport by the binding motifs KCO1 is expressed in low amounts in Arabdopsis and is not localized to any particulartissue, being found in whole seedlings, leaves, and flowers. 通過酶消化，特異性地將原生質(zhì)體從木質(zhì)部導(dǎo)管周圍的木薄壁組織種釋放出來，利用膜片鉗技術(shù)研究確定 3種類型的離子通道： K＋ 進(jìn) 通道和另外兩種通道 ——一種對 K＋ 有選擇性，另一種無選擇性。 The cloning of highaffinity K+ transporters The first highaffinity K+ transporter, HKT1, was cloned by plementation of yeast trk1trk2 K+ transport mutant with a cDNA library a mass of 59 kDa and contain 12 membranespanning domains Expression of HKT1 in Xenopus oocytes gave rise to large inward currents in the present of K+. Expression of HKT1 in yeast shows Km=29181。M Expression of HKT1 in plant is localized to root cortex, stele and leaves, but not in root epidermis. The expression of HKT1 was proposed to be a K+ Na+ cotransporter that mediates highaffinity K+ uptake. control HKT1 HKT1 control The expression of HKT1 in yeast yielded Na+stimulated Rb+ uptake (A), and K+stimulated Na+ uptake (B) . Yeast AtKUP1 and AtKUP2 are the members of another family of genes encoding highaffinity K+ transporters. Concentrationdependent kiics of Rb+ uptake in transgenic Arabidopsis suspension cells with 35SAtKUP1 (red) and an empty vector (blue ). (A)Mediating a highaffinity system。 (B)Facilitating a lowaffinity system 克隆到的編碼 K+轉(zhuǎn)運蛋白的植物基因小結(jié) 基因 物種 定位 KAT1 擬南芥 保衛(wèi)細(xì)胞和維管組織 KST1 馬鈴薯 保衛(wèi)細(xì)胞和花芽 AKT1 擬南芥 表皮和皮層根組織 AKT2/13 擬南芥 葉 SKT1 馬鈴薯 根、葉的表皮組織 SKT2 馬鈴薯 ？ SKT3 馬鈴薯 ？ KCO1 擬南芥 花，全株小苗，葉 SKOR 擬南芥 根星型細(xì)胞 HKT1 小麥 根內(nèi)皮層、根維管結(jié)構(gòu) AtKUP1 擬南芥 根、葉、花 AtKUP2 擬南芥 根、葉、花 HvHAK1 大麥 根 Low K+ : 40 181。M, High K+: 20 mM Root
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