Sparvoli F, Gallo A, Marinelli D, Santucci A, Bollini R
Istituto Biosintesi Vegetali, CNR, Milan, Italy.
Biochim Biophys Acta. 1998 Feb 17;1382(2):311-23. doi: 10.1016/s0167-4838(97)00168-4.
The only component of the lectin-related protein family so far reported in Lima bean (Phaseolus lunatus L.) seeds is the minor seed lectin (LBL). In the morphotype Big Lima, we have isolated and characterised two abundant lectin-related seed proteins and the corresponding cDNA clones. The clones show 93.7% nucleotide identity and encode an arcelin-like (ARL) and an alpha-amylase inhibitor-like (AIL) protein. Not considering the signal peptides, ARL and AIL polypeptides contain 239 and 233 amino acids, respectively. Each polypeptide is present in the mature protein as two glycoforms. ARL subunits (43 and 46 kDa) make up oligomers of about 125 to 130 kDa whereas AIL subunits (40 and 42 kDa) oligomerise in dimers of about 88 to 100 kDa. cDNA clones encoding two isoforms of the less abundant Lima bean lectin were also isolated. In common bean (P. vulgaris) the lectin locus encodes the lectin and the lectin-related proteins alpha-amylase inhibitor and arcelin, all plant defence proteins. Our data indicate extensive evolution of the locus also in Lima bean.
菜豆（Phaseolus lunatus L.）种子中迄今报道的凝集素相关蛋白家族的唯一成分是次要种子凝集素（LBL）。在“大莱豆”形态类型中，我们分离并鉴定了两种丰富的凝集素相关种子蛋白以及相应的cDNA克隆。这些克隆显示出93.7%的核苷酸同一性，编码一种类arc蛋白（ARL）和一种类α-淀粉酶抑制剂蛋白（AIL）。不考虑信号肽，ARL和AIL多肽分别含有239和233个氨基酸。每种多肽在成熟蛋白中以两种糖型存在。ARL亚基（43和46 kDa）组成约125至130 kDa的寡聚体，而AIL亚基（40和42 kDa）则以约88至100 kDa的二聚体形式寡聚化。还分离出了编码含量较少的菜豆凝集素两种同工型的cDNA克隆。在普通菜豆（P. vulgaris）中，凝集素基因座编码凝集素以及凝集素相关蛋白α-淀粉酶抑制剂和arc蛋白，它们都是植物防御蛋白。我们的数据表明，该基因座在菜豆中也发生了广泛的进化。
