Stipe wall extension of Flammulina velutipes could be induced by an expansin-like protein from Helix aspersa
Stipe wall extension of Flammulina velutipes could be induced by an expansin-like protein from Helix aspersa
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Helix aspersa 的类扩展蛋白可诱导金针菇菌柄壁延伸
DOI：
10.1016/j.funbio.2013.10.003
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发表时间：
2014-01-01
期刊：
影响因子：
2.5
通讯作者：
Yuan, Sheng
中科院分区：
文献类型：
--
作者：
Fang, Hejian;Zhang, Wenming;Yuan, Sheng
膨胀蛋白通过破坏细胞壁多糖之间的氢键的无水解过程来延长植物细胞壁。然而，尚不清楚这种机制是否在蘑菇中起作用。在这里，我们报告说，本地壁延伸活动是专门位于30毫米金针菇柄顶端区域的10毫米。伸长生长也被限制在柄的9 mm顶端区域，其中第1毫米的伸长生长是第5毫米的伸长生长的40倍。因此，壁延伸活动代表菌柄的伸长生长。F. velutipesstipes阻止了其分离。然而，我们从蜗牛胃液中纯化了一种膨胀蛋白样蛋白，它重建了热灭活的柄壁延伸，而没有水解活性。因此，以往认为菌柄壁的延伸是由于酶水解壁聚合物或膨压破坏壁聚合物的氢键的假说受到了挑战。我们认为，菌柄壁的延伸可能介导的内源性扩张素样蛋白，促进细胞壁聚合物滑移破坏葡聚糖链或几丁质链之间的非共价键合。(C)2013年英国真菌学会。由爱思唯尔有限公司出版。保留所有权利。
Expansin proteins extend plant cell walls by a hydrolysis-free process that disrupts hydrogen bonding between cell wall polysaccharides. However, it is unknown if this mechanism is operative in mushrooms. Herein we report that the native wall extension activity was located exclusively in the 10 mm apical region of 30 mm Flammulina velutipes stipes. The elongation growth was restricted also to the 9 mm apical region of the stipes where the elongation growth of the 1st millimetre was 40-fold greater than that of the 5th millimetre. Therefore, the wall extension activity represents elongation growth of the stipe. The low concentration of expansin-like protein in F. velutipes stipes prevented its isolation. However, we purified an expansinlike protein from snail stomach juice which reconstituted heat-inactivated stipe wall extension without hydrolytic activity. So the previous hypotheses that stipe wall extension was resulted from hydrolysis of wall polymers by enzymes or disruption of hydrogen bonding of wall polymers exclusively by turgor pressure are challenged. We suggest that stipe wall extension may be mediated by endogenous expansin-like proteins that facilitate cell wall polymer slippage by disrupting noncovalent bonding between glucan chains or chitin chains. (C) 2013 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.