CAJ | 학술논문

5-氨基乙酰丙酸脱水酶(δ-aminoaevulinic acid dehydratase, ALAD)是生物体所有四吡咯化合物生物合成所必需的酶。目前，GenBank共记载了39种绿色植物的ALAD基因。本文采用生物信息学方法对其中常用的模式植物拟南芥、玉米、小麦、大豆、苜蓿以及葡萄、菠菜等植物的5-氨基乙酰丙酸脱水酶基因的核苷酸及其编码的蛋白氨基酸序列、组成成分、导肽、信号肽、跨膜结构域、疏水性/亲水性、蛋白质二级结构、三级结构及功能域等进行预测和分析，并构建了5-氨基乙酰丙酸脱水酶蛋白家族的系统进化树。结果表明，这几种植物的开放阅读框都在1290 bp左右，分子量为47 kD左右，等电点(pI)值为5.5~7.0之间，ALAD蛋白呈中性至微酸性。含量最丰富的氨基酸为Ala、Leu、Val、Arg、Ser、Gly、Pro和Asp。研究还发现这些植物5-氨基乙酰丙酸脱水酶肽链表现出明显的疏水区和亲水区，不存在信号肽，有叶绿体转运肽；可能存在跨膜结构域。蛋白质二级结构中最主要的结构元件是无规则卷曲和α-螺旋，含有5-氨基乙酰丙酸脱水酶的活性结构域、ALAD-PGBS-aspartate-rich保守结构域、舍夫碱残基结构域和一个镁离子结合位点结构域。核苷酸同源性比对结果显示，拟南芥5-氨基乙酰丙酸脱水酶基因与其它植物的同源性较高；进化分析结果表明这些植物5-氨基乙酰丙酸脱水酶基因被分为六个大类。本工作可为今后深入研究植物5-氨基乙酰丙酸脱水酶的结构特征和功能提供一定的依据。
5-안기을선병산탈수매(δ-aminoaevulinic acid dehydratase, ALAD)시생물체소유사필각화합물생물합성소필수적매。목전，GenBank공기재료39충록색식물적ALAD기인。본문채용생물신식학방법대기중상용적모식식물의남개、옥미、소맥、대두、목숙이급포도、파채등식물적5-안기을선병산탈수매기인적핵감산급기편마적단백안기산서렬、조성성분、도태、신호태、과막결구역、소수성/친수성、단백질이급결구、삼급결구급공능역등진행예측화분석，병구건료5-안기을선병산탈수매단백가족적계통진화수。결과표명，저궤충식물적개방열독광도재1290 bp좌우，분자량위47 kD좌우，등전점(pI)치위5.5~7.0지간，ALAD단백정중성지미산성。함량최봉부적안기산위Ala、Leu、Val、Arg、Ser、Gly、Pro화Asp。연구환발현저사식물5-안기을선병산탈수매태련표현출명현적소수구화친수구，불존재신호태，유협록체전운태；가능존재과막결구역。단백질이급결구중최주요적결구원건시무규칙권곡화α-라선，함유5-안기을선병산탈수매적활성결구역、ALAD-PGBS-aspartate-rich보수결구역、사부감잔기결구역화일개미리자결합위점결구역。핵감산동원성비대결과현시，의남개5-안기을선병산탈수매기인여기타식물적동원성교고；진화분석결과표명저사식물5-안기을선병산탈수매기인피분위륙개대류。본공작가위금후심입연구식물5-안기을선병산탈수매적결구특정화공능제공일정적의거。
δ-aminoaevulinic acid dehydratase is necessary to the biosynthesis of porphyrin compounds in all organ-isms. At present, 39 greenery ALAD genes have been recorded in Gen Bank. In this paper, the nucleic acid sequences and amino acid sequences of ALAD gene from model plant, such as A rabidopsis thaliana, Zea may, Triticum urartu, Glycine max,Medicago truncatula,Vitis vinifera,and Spinaciao leracea wereanalyzed by bioin formatics,includingthe composition of nucleic acid sequences and amino acid sequences, leader peptides, signal peptide, trans-membrane topological structure, hydrohobicity or hydrophilicity, secondary structure, tertiary structure and functional domains of protein and so on. Phylogenetic tree was constructed for the δ-aminoaevulinic acid dehydratase protein family. Results showed that the open reading frame (ORF) of samples is about 1 290, the molecular weight is about 47 kD, the pI is 5.5~7.0 which illustrated that δ-aminoaevulinic acid dehydratase is neutral to slightly acidic. The most abundant amino acids residues are Ala, Leu, Val, Arg, Ser, Gly, Pro and Asp. The study also showed that the ALAD protein peptide of these plants showed obvious hydrophobicity area and hydrophilicity area, chloroplast transit peptide;may exists a small amount of trans-membrane topological structure, no signal peptide. The main secondary structures of the proteins are random coil and Alpha helix. All these proteins have active site, Schiff base residues,aspartate-rich active site metal binding site and Allosteric magnesium binding site. The nucleotide homology com-parison indicated that A rabidopsis thaliana shared a high homology with other plants. Evolutionary analysis demon-strated that these proteins can be classified into six clusters. Those works would provide the basis for further study of the function and structure characteristis of δ-aminoaevulinic acid dehydratase in future.