Nucleotide Sequence of S-Adenosyl-l-Methionine: Magnesium Protoporphyrin Methyltransferase from Rhodobacter capsulatus.
Nucleotide Sequence of S-Adenosyl-l-Methionine: Magnesium Protoporphyrin Methyltransferase from Rhodobacter capsulatus.
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S-腺苷-l-甲硫氨酸的核苷酸序列：来自荚膜红杆菌的镁原卟啉甲基转移酶。
DOI：
10.1104/pp.98.1.408
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发表时间：
1992
期刊：
影响因子：
7.4
通讯作者：
Bauer,CE
中科院分区：
文献类型：
--
作者：
Bollivar,DW;Bauer,CE
一般认为Chl与细菌叶绿素生物合成是进化相关的。这一假设得到以下观察结果的支持：Chl a的生物合成途径涉及与细菌-叶绿素a生物合成共同存在的中间体（参见文献7），以及观察到原叶绿素-phyllide不依赖于光的还原涉及一种在紫色光合细菌和植物之间高度保守的酶复合物（J. Suzuki和C. Bauer，未发表的数据）。因此，光合细菌为研究参与Chl生物合成的酶提供了一个很好的模型系统。荚膜红杆菌（Rhodobacter capsulatus）具有在非光合（异养）条件下快速生长的能力，因此，特别适合色素生物合成的遗传分析。已经分离出许多缺乏细菌叶绿素生物合成的突变体，它们在mg -四吡咯生物合成途径中积累了不同的中间体（9,10）。特别令人感兴趣的是bchHgene的突变，据报道缺乏s -腺苷基- l-蛋氨酸：镁原卟啉甲基转移酶活性，催化甲基从s -腺苷基- l-蛋氨酸转移到mg -原卟啉IX的第6丙基(6)。bchH序列（表1，图1）编码1195个残基的大多肽。预测的蛋白没有明显的跨膜区，其平均疏水性（-0.116）是可溶性蛋白的典型特征(4)。它在Genbank数据库中没有容易识别的同源物。
It is generally believed that Chl and bacteriochlorophyll biosynthesis are evolutionarily related. This supposition is supported by the observation that the biosynthetic pathway for Chl a involves intermediates that are common with bac-teriochlorophyll a biosynthesis (reviewed in ref. 7) and by the observation that light-independent reduction of protochloro-phyllide to Chlide involves an enzyme complex that is highly conserved between purple photosynthetic bacteria and plants (J. Suzuki and C. Bauer, unpublished data). Thus, photosynthetic bacteria offer a good model system for studying enzymes involved in Chl biosynthesis. The bacterium Rhodobacter capsulatus has the capability to undergo rapid growth under nonphotosynthetic (hetero-trophic) conditions and is, therefore, particularly amenable to a genetic analysis ofpigment biosynthesis. Numerous mutants deficient in bacteriochlorophyll biosynthesis have been isolated that accumulate different intermediates in the Mg-tetra-pyrrole biosynthetic pathway (9, 10). Of particular interest are mutations in the bchHgene which are reported to lack S-adenosyl-L-methionine: magnesium protoporphyrin methyltransferase activity which catalyzes the transfer of a methyl group from S-adenosyl-L-methionine to the sixth propyl group of Mg-protoporphyrin IX (6). The sequence of bchH (Table I, Fig. 1) encodes a large polypeptide of 1195 residues. The predicted protein has no apparent membrane-spanning region and its mean hydrophobicity (-0.116) is typical of soluble proteins (4). It has no readily identifiable homolog in the Genbank data base.
大麦 S-腺苷-L-甲硫氨酸-镁-原卟啉 IX 甲基转移酶的特性
影响因子：
4.9
作者：
J. Shieh;G. Miller;M. Pšenák
通讯作者：
M. Pšenák