Biochemical and proteomic analysis of the magnetosome membrane in Magnetospitillum gryphiswaldense
Biochemical and proteomic analysis of the magnetosome membrane in Magnetospitillum gryphiswaldense
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DOI：
10.1128/aem.70.2.1040-1050.2004
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发表时间：
2004-02-01
影响因子：
4.4
通讯作者：
Schüler, D
中科院分区：
文献类型：
--
作者：
Grünberg, K;Müller, EC;Schüler, D
对格雷氏磁螺菌的磁小体膜生化组成进行了分析。分离的磁小体与磷脂和脂肪酸结合在一起，这些磷脂和脂肪酸类似于来自其他亚细胞隔室(即外膜和细胞质膜)的磷脂和脂肪酸，但存在比例不同。通过选择性增溶和有限蛋白水解法研究MM相关蛋白的结合特性。进一步用蛋白质组学方法对MM相关蛋白进行了分析，包括一维和二维十二烷基硫酸钠-聚丙烯酰胺凝胶电泳、Edman和质谱仪(电喷雾电离-质谱联用)测序，以及毛细管液相色谱-质谱仪-质谱仪对MM的总胰酶消化进行分析，发现至少有18个蛋白质组成磁小体亚蛋白质组，其中大多数是格里菲斯瓦登氏支原体的新蛋白质。除MM22和MMS16外，所有真正的MM蛋白(MMPs)都是由先前发现的磁小体岛中的maMAB、maMDC和MMS6簇的开放阅读框编码的。其中8个MMP与已知家族同源，其中一些以多个同源形式出现在MM中。其中10个MMP在非磁性生物中没有已知的同源物，因此代表了新的趋磁细菌特异性蛋白家族。几个MMP显示重复或高度酸性的序列模式，这是从其他生物矿化系统中已知的，因此可能与磁铁矿的形成有关。
We analyzed the biochemical composition of the magnetosome membrane (MM) in Magnetospirillum gryphiswaldense. Isolated magnetosomes were associated with phospholipids and fatty acids which were similar to phospholipids and fatty acids from other subcellular compartments (i.e., outer and cytoplasmic membranes) but were present in different proportions. The binding characteristics of MM-associated proteins were studied by selective solubilization and limited proteolysis. The MM-associated proteins were further analyzed by various proteomic approaches, including one- and two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by Edman and mass spectrometric (electrospray ionization-mass spectrometry-mass spectrometry) sequencing, as well as capillary liquid chromatography-mass spectrometry-mass spectrometry of total tryptic digests of the MM. At least 18 proteins were found to constitute the magnetosome subproteome, and most of these proteins are novel for M. gryphiswaldense. Except for MM22 and Mms16, all bona fide MM proteins (MMPs) were encoded by open reading frames in the mamAB, mamDC, and mms6 clusters in the previously identified putative magnetosome island. Eight of the MMPs display homology to known families, and some of them occur in the MM in multiple homologues. Ten of the MMPs have no known homologues in nonmagnetic organisms and thus represent novel, magnetotactic bacterium-specific protein families. Several MMPs display repetitive or highly acidic sequence patterns, which are known from other biomineralizing systems and thus may have relevance for magnetite formation.