MMBL proteins: from lectin to bacteriocin
MMBL proteins: from lectin to bacteriocin
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DOI：
10.1042/bst20120170
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发表时间：
2012-12-01
影响因子：
3.9
通讯作者：
De Mot, Rene
中科院分区：
文献类型：
--
作者：
Ghequire, Maarten G. K.;Loris, Remy;De Mot, Rene
可以说，在相关细菌之间的战争中部署的细菌素是结构和作用方式最多样化的蛋白质化合物之一。MMBLs（单子叶植物甘露糖结合凝集素）或GNA（雪花莲凝集素）凝集素家族的第一个原核成员的鉴定及其在革兰氏阴性菌假单胞菌和黄单胞菌中的属特异性杀伤活性的发现为这组化感作用分子添加了另一种毒素。这种新的功能是让人想起的保护功能，抗真菌，杀虫，杀线虫或抗病毒活性的基础上，分配或建议的几个真核MMBL蛋白，是普遍分布在单子叶植物，但也出现在一些其他植物，鱼类，海绵，变形虫和真菌。C型凝集素也可影响直接杀菌活性，但这是一种限制革兰氏阳性菌在粘膜定植的哺乳动物蛋白。两个不同的MMBL结构域的存在下，在新的细菌素提出的问题模块之间的任务分配和可能的作用，碳水化合物结合的特异性，目标菌株的识别和杀伤。值得注意的是，细菌素活性也证明了一个混合MMBL蛋白与辅助蛋白酶样结构域。这种关联与一个或多个额外的模块，通常与预测的肽水解或结合活性，表明可能会发现额外的细菌毒性蛋白质之间的不同嵌合MMBL蛋白质编码的原核基因组。的细菌MMBL模块的系统发育调查揭示了马赛克模式的强烈分歧的序列，主要发生在土壤和根际细菌，这可能反映了跨王国收购的祖先基因。
Arguably, bacteriocins deployed in warfare among related bacteria are among the most diverse proteinacous compounds with respect to structure and mode of action. Identification of the first prokaryotic member of the so-called MMBLs (monocot mannose-binding lectins) or GNA (Galanthus nivalis agglutinin) lectin family and discovery of its genus-specific killer activity in the Gram-negative bacteria Pseudomonas and Xanthomonas has added yet another kind of toxin to this group of allelopathic molecules. This novel feature is reminiscent of the protective function, on the basis of antifungal, insecticidal, nematicidal or antiviral activity, assigned to or proposed for several of the eukaryotic MMBL proteins that are ubiquitously distributed among monocot plants, but also occur in some other plants, fish, sponges, amoebae and fungi. Direct bactericidal activity can also be effected by a C-type lectin, but this is a mammalian protein that limits mucosal colonization by Gram-positive bacteria. The presence of two divergent MMBL domains in the novel bacteriocins raises questions about task distribution between modules and the possible role of carbohydrate binding in the specificity of target strain recognition and killing. Notably, bacteriocin activity was also demonstrated for a hybrid MMBL protein with an accessory protease-like domain. This association with one or more additional modules, often with predicted peptide-hydrolysing or -binding activity, suggests that additional bacteriotoxic proteins may be found among the diverse chimaeric MMBL proteins encoded in prokaryotic genomes. A phylogenetic survey of the bacterial MMBL modules reveals a mosaic pattern of strongly diverged sequences, mainly occurring in soil-dwelling and rhizosphere bacteria, which may reflect a trans-kingdom acquisition of the ancestral genes.