Abstract
Chitinase-A (EaChiA), molecular mass 36 kDa, was purified from the vegetative stems of a horsetail (Equisetum arvense) using a series of column chromatography. The N-terminal amino acid sequence of EaChiA was similar to the lysin motif (LysM). A cDNA encoding EaChiA was cloned by rapid amplification of cDNA ends and polymerase chain reaction. It consisted of 1320 nucleotides and encoded an open reading frame of 361 amino acid residues. The deduced amino acid sequence indicated that EaChiA is composed of a N-terminal LysM domain and a C-terminal plant class IIIb chitinase catalytic domain, belonging to the glycoside hydrolase family 18, linked by proline-rich regions. EaChiA has strong chitin-binding activity, however, no antifungal activity. This is the first report of a chitinase from Equisetopsida, a class of fern plants, and the second report of a LysM-containing chitinase from a plant.
摘要:从一种
铁线莲(Equisetum arvense)的营养茎中纯化出分子量为36 kDa的
壳聚糖酶A(EaChiA),使用一系列柱层析技术。EaChiA的N末端
氨基酸序列与赖
氨酸基序(LysM)相似。通过快速扩增cDNA末端和聚合酶链反应克隆了编码EaChiA的cDNA。它由1320个核苷酸组成,编码一个361个
氨基酸残基的开放阅读框。推测的
氨基酸序列表明,EaChiA由一个N末端LysM结构域和一个C末端植物IIIb类
壳聚糖酶催化结构域组成,属于18号糖苷
水解酶家族,通过富含脯
氨酸的区域连接。EaChiA具有强
壳聚糖结合活性,但没有抗真菌活性。这是首次报道了来自蕨类植物Equisetopsida的
壳聚糖酶,也是来自植物的第二份含有LysM的
壳聚糖酶的报道。