Molecular and genetic characterization of the rhizopine catabolism (mocABRC) genes of Rhizobium meliloti L5-30
Molecular and genetic characterization of the rhizopine catabolism (mocABRC) genes of Rhizobium meliloti L5-30
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苜蓿根瘤菌 L5-30 根瘤平分解代谢 (mocABRC) 基因的分子和遗传特征
DOI：
10.1007/bf00279746
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
F. J. Bruijn
中科院分区：
文献类型：
--
作者：
S. Rossbach;D. Kulpa;U. Rossbach;F. J. Bruijn
Rhizopine（1 -3-O-methyl-scyllo-inosamine，3-O-MSI）是苜蓿根瘤菌（Rhizobium meliloti）菌株L5-30诱导苜蓿根瘤中合成的一种共生专一性化合物。3-O-MSI被认为是R.苜蓿L5-30，其携带负责其合成的基因座（mos），该基因座与负责其降解的基因座（moc）紧密相连。在这里，必需的moc基因由Tn 5诱变限定，并显示被组织成两个区域，由3 kb的DNA分开。确定了跨越两个MOC区域的9-kb片段的DNA序列，并确定了在根碱catalysts中发挥重要作用的四个基因（mocABC和mocR）。DNA序列和推导的蛋白质产物的氨基酸序列的分析表明，莫卡类似于NADH依赖的脱氢酶。MocB表现出周质结合蛋白的特征，这些蛋白是高亲和力运输系统的组成部分。MocC与数据库中的任何蛋白质都没有显著的同源性。MocR显示与GntR类细菌调节蛋白的同源性。这些结果表明，mocABC基因参与的吸收和随后的降解的rhizopine，而mocR可能发挥调节作用。
Rhizopine (l-3-O-methyl-scyllo-inosamine, 3-O-MSI) is a symbiosis-specific compound, which is synthesized in nitrogen-fixing nodules of Medicago sativa induced by Rhizobium meliloti strain L5–30. 3-O-MSI is thought to function as an unusual growth substrate for R. meliloti L5–30, which carries a locus (mos) responsible for its synthesis closely linked to a locus (moc) responsible for its degradation. Here, the essential moc genes were delimited by Tn5 mutagenesis and shown to be organized into two regions, separated by 3 kb of DNA. The DNA sequence of a 9-kb fragment spanning the two moc regions was determined, and four genes were identified that play an essential role in rhizopine catabolism (mocABC and mocR). The analysis of the DNA sequence and the amino acid sequence of the deduced protein products revealed that MocA resembles NADH-dependent dehydrogenases. MocB exhibits characteristic features of periplasmic-binding proteins that are components of high-affinity transport systems. MocC does not share significant homology with any protein in the database. MocR shows homology with the GntR class of bacterial regulator proteins. These results suggest that the mocABC genes are involved in the uptake and subsequent degradation of rhizopine, whereas mocR is likely to play a regulatory role.
大肠杆菌 K12 的 D-核糖结合蛋白的氨基酸序列。
DOI：
--
发表时间：
1983
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Groarke,JM;Mahoney,WC;Hope,JN;Furlong,CE;Robb,FT;Zalkin,H;Hermodson,MA
通讯作者：
Hermodson,MA