Amino acid sequences of lysozymes newly purified from invertebrates imply wide distribution of a novel class in the lysozyme family
Amino acid sequences of lysozymes newly purified from invertebrates imply wide distribution of a novel class in the lysozyme family
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DOI：
10.1046/j.1432-1327.1999.00064.x
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发表时间：
1999-01-01
期刊：
影响因子：
--
通讯作者：
Imoto, T
中科院分区：
文献类型：
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作者：
Ito, Y;Yoshikawa, A;Imoto, T
从三种无脊椎动物中纯化溶菌酶：海洋双壳类，海洋海螺和海洋贝类。纯化的溶菌酶在SDS/PAGE上显示相似的分子量为13 kDa。它们的N-末端序列到第33位残基在这里被确定显然是它们之间的同源性，此外，他们有一个同源性的部分序列的海星溶菌酶已报道。通过肽图和随后的序列分析确定了双壳类溶菌酶的完整序列。这是由123个氨基酸，包括多达14个半胱氨酸残基，并没有显示出明确的同源性与已知类型的溶菌酶。然而，在蛋白质或核酸数据库上对该蛋白质进行同源性搜索，发现两个同源蛋白质。其中一个是C.这是一种功能未知的蛋白质。另一种是药用水蛭的异肽酶，名为去稳定酶。因此，在无脊椎动物的三个类别中的至少四个物种中发现的新型溶菌酶证明了无脊椎动物中的一类新的蛋白质/溶菌酶家族。这里首次表征的双壳溶菌酶显示出极高的蛋白质稳定性和类似母鸡溶菌酶的酶特征。
Lysozymes were purified from three invertebrates: a marine bivalve, a marine conch. and an earthworm. The purified lysozymes all showed a similar molecular weight of 13 kDa on SDS/PAGE. Their N-terminal sequences up to the 33rd residue determined here were apparently homologous among them; in addition, they had a homology with a partial sequence of a starfish lysozyme which had been reported before. The complete sequence of the bivalve lysozyme was determined by peptide mapping and subsequent sequence analysis. This was composed of 123 amino acids including as many as 14 cysteine residues and did not show a clear homology with the known types of lysozymes. However, the homology search of this protein on the protein or nucleic acid database revealed two homologous proteins. One of them was a gene product, CELF22 A3.6 of C. elegans, which was a functionally unknown protein. The other was an isopeptidase of a medicinal leech, named destabilase. Thus, a new type of lysozyme found in at least four species across the three classes of the invertebrates demonstrates a novel class of protein/lysozyme family in invertebrates. The bivalve lysozyme, first characterized here, showed extremely high protein stability and hen lysozyme-like enzymatic features.