Spinelli F, Mariotti L, Mattei B, Salvi G, Cervone F, Caprari C
Dipartimento di Biologia Vegetale, Università di Roma La Sapienza, Rome, Italy.
Plant Biol (Stuttg). 2009 Sep;11(5):738-43. doi: 10.1111/j.1438-8677.2008.00175.x.
Polygalacturonase-inhibiting proteins (PGIPs) are plant cell wall proteins that specifically inhibit the activity of endopolygalacturonases (PGs) produced by fungi during the infection process. The interaction with PGIPs limits the destructive potential of PGs and may trigger plant defence responses through the release of elicitor active oligogalacturonides. In order to pinpoint the residues of PvPGIP2 from Phaseolus vulgaris involved in the interaction with PGs, we used site-directed mutagenesis to mutate the residues D131, D157 and D203, and tested for the inhibitory activity of the mutant proteins expressed in Pichia pastoris against Fusarium phyllophilum and Aspergillus niger PGs. Here, we report that mutation of these residues affects the inhibition capacity of PvPGIP2 against F. phyllophilum PG.
多聚半乳糖醛酸酶抑制蛋白（PGIPs）是植物细胞壁蛋白，在感染过程中能特异性抑制真菌产生的内切多聚半乳糖醛酸酶（PGs）的活性。与PGIPs的相互作用限制了PGs的破坏潜力，并可能通过释放激发子活性寡聚半乳糖醛酸引发植物防御反应。为了确定菜豆PvPGIP2中参与与PGs相互作用的残基，我们使用定点诱变对残基D131、D157和D203进行突变，并测试了在毕赤酵母中表达的突变蛋白对嗜叶镰刀菌和黑曲霉PGs的抑制活性。在此，我们报告这些残基的突变会影响PvPGIP2对嗜叶镰刀菌PG的抑制能力。
