Sequence of a cDNA Clone Encoding a Potato (Solanum tuberosum) Tuber Lipoxygenase
Sequence of a cDNA Clone Encoding a Potato (Solanum tuberosum) Tuber Lipoxygenase
复制标题
编码马铃薯（Solanum tuberosum）块茎脂氧合酶的 cDNA 克隆的序列
作者：
R. Casey
LOX （EC 1.13.11.12）是普遍存在的植物酶，催化多不饱和脂肪酸的氢过氧化作用；马铃薯块茎含有高浓度的液态氧（Pinsky et al., 1971）。LOX被认为催化了茉莉酸盐形成的关键步骤，茉莉酸盐对植物生理和基因表达有深远的影响（Staswick, 1992），包括诱导马铃薯的薯类形成（Koda et al., 1991）。LOX也与花生四烯酸引起的马铃薯盘和愈伤组织的超敏感细胞死亡反应有关（Bostock等，1992；Vaughn和Lulai， 1992）。经纯化的马铃薯马铃薯LOX主要在花生四烯酸的5碳上产生氢过氧化作用（Shimizu等人，1990），因此在位置特异性上不同于已被充分表征的大豆种子花生四烯酸15-LOX (Boyington等人，1993)；对其结构的分析可能为植物液氧过氧化作用的位置特异性提供线索。本文报道了一种loxl:St:Z基因，该基因与发育中块茎中丰富的mRNA相对应。该序列如表1所示，在终止密码子和poly(A) tail之间有200 bp，在起始密码子之间有1 bp 5'。所提出的起始ATG与其他同源植物LOX序列吻合良好；利用核苷酸2 ~ 22对应的寡核苷酸进行引物延伸，马铃薯块茎LOX mRNA有74个核苷酸的5′非编码序列。10x2: St:2预测的氨基酸序列与Melan et al.（1994）报道的Arubidopsis thuliunu LOX 1序列的相似性高于其他已发表的LOX序列，与Arubidopsis LOX 1的相似性为80%（一致性为66%）。Boyington等人（1993）描述了大豆15-LOX的内部空腔（11），可能容纳脂肪酸底物。在这个空腔中，他们描述了14种高度保守的氨基酸；这些在从1oxl:St:Z预测的序列中也是保守的。空腔中的一个残基（Phe557）可能参与位置特异性的确定(见
LOX (EC 1.13.11.12) are ubiquitous plant enzymes that catalyze the hydroperoxidation of polyunsaturated fatty acids; potato tubers contain high levels of LOX (Pinsky et al., 1971). LOX are believed to catalyze a key step in the formation of jasmonates, which have profound effects on plant physiology and gene expression (Staswick, 1992), including the induction of tuber formation in potatoes (Koda et al., 1991). LOX have also been implicated in the arachidonic acid-elicited hypersensitive cell death response of potato discs and callus lines (Bostock et al., 1992; Vaughn and Lulai, 1992). The potato tuber LOX that has been purified effects hydroperoxidation predominantly at the 5-carbon of arachidonic acid (Shimizu et al., 1990) and thus differs in positional specificity from the well-characterized soybean seed arachidonate 15-LOX (Boyington et al., 1993); analysis of its structure may afford clues to the basis of positional specificity of hydroperoxidation by plant LOX. This report describes loxl:St:Z, a Solanum tuberosum LOX cDNA that corresponds to mRNA that is abundant in developing tubers. The sequence, described in Table I, includes 200 bp between the stop codon and the poly(A) tail, and 1 bp 5' to the initiation codon. The proposed initiating ATG aligns well with other, homologous plant LOX sequences; primer extension using an oligonucleotide corresponding to nucleotides 2 to 22 indicates that the potato tuber LOX mRNA has 74 nucleotides of 5' noncoding sequence. The amino acid sequence predicted by 10x2: St:2 is more similar to the Arubidopsis thuliunu LOX 1 sequence reported by Melan et al. (1994) than to any other published LOX sequence, showing 80% similarity (66% identity) to Arubidopsis LOX 1. Boyington et al. (1993) described an interna1 cavity (11) in soybean 15-LOX that is likely to accommodate the fatty acid substrate. Within this cavity they described 14 highly conserved amino acids; these are also conserved in the sequence predicted from 1oxl:St:Z. One residue (Phe557) in the cavity may be involved in the determination of positional specificity (see
影响因子：
56.9
作者：
BOYINGTON, JC;GAFFNEY, BJ;AMZEL, LM
通讯作者：
AMZEL, LM