Molecular annotation of ketol-acid reductoisomerases from Streptomyces reveals a novel amino acid biosynthesis interlock mediated by enzyme promiscuity.
Molecular annotation of ketol-acid reductoisomerases from Streptomyces reveals a novel amino acid biosynthesis interlock mediated by enzyme promiscuity.
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DOI：
10.1111/1751-7915.12175
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发表时间：
2015-03
影响因子：
5.7
通讯作者：
Barona-Gómez F
中科院分区：
文献类型：
--
作者：
Verdel-Aranda K;López-Cortina ST;Hodgson DA;Barona-Gómez F
6-磷酸葡萄糖酸脱氢酶超家族氧化和还原广泛的底物，使其功能注释具有挑战性。酮醇酸还原异构酶（KARI）是由支链氨基酸生物合成中的ilvC基因编码的，是该超家族中的一种混杂还原酶。在这里，我们获得稳态酶动力学参数为10 IlvC同系物链霉菌属和棒状杆菌属，在8个选定的化学不同的基板，包括一些通常不承认的酶的这个超家族。这一生化数据表明链霉菌生物合成之间的连锁脯氨酸和支链氨基酸，介导的酶底物混杂，这是证实了通过诱变和互补分析的proC，ilvC 1和ilvC 2基因天蓝色链霉菌。此外，分析了ilvC直向同源物和旁系同源物，从而可以探索基因重复和功能多样化之间的关系。在天蓝色链霉菌和变铅青链霉菌中存在的KARI旁系同源物，尽管其保守的高序列同一性（97%），但显示出更混杂，表明最近的功能多样化。相比之下，来自Streptomyces viridifaciens的KARI paradigase显示出对缬氨酸前体合成的选择性，解释了其在valanimycin的生物合成基因簇内的募集。这些结果使我们能够评估底物混杂指数作为一种工具来注释新的分子功能与代谢的影响。
The 6-phosphogluconate dehydrogenase superfamily oxidize and reduce a wide range of substrates, making their functional annotation challenging. Ketol-acid reductoisomerase (KARI), encoded by the ilvC gene in branched-chain amino acids biosynthesis, is a promiscuous reductase enzyme within this superfamily. Here, we obtain steady-state enzyme kinetic parameters for 10 IlvC homologues from the genera Streptomyces and Corynebacterium, upon eight selected chemically diverse substrates, including some not normally recognized by enzymes of this superfamily. This biochemical data suggested a Streptomyces biosynthetic interlock between proline and the branched-chain amino acids, mediated by enzyme substrate promiscuity, which was confirmed via mutagenesis and complementation analyses of the proC, ilvC1 and ilvC2 genes in Streptomyces coelicolor. Moreover, both ilvC orthologues and paralogues were analysed, such that the relationship between gene duplication and functional diversification could be explored. The KARI paralogues present in S. coelicolor and Streptomyces lividans, despite their conserved high sequence identity (97%), were shown to be more promiscuous, suggesting a recent functional diversification. In contrast, the KARI paralogue from Streptomyces viridifaciens showed selectivity towards the synthesis of valine precursors, explaining its recruitment within the biosynthetic gene cluster of valanimycin. These results allowed us to assess substrate promiscuity indices as a tool to annotate new molecular functions with metabolic implications.
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影响因子：
3.6
作者：
Garg, RP;Ma, YQ;Parry, RJ
通讯作者：
Parry, RJ
影响因子：
11.4
作者：
Biou, V;Dumas, R;PebayPeyroula, E
通讯作者：
PebayPeyroula, E
影响因子：
2.9
作者：
Kim, Juhan;Copley, Shelley D.
通讯作者：
Copley, Shelley D.
大肠杆菌K-12的构造框架，单基因敲除突变体：Keio Collection。
影响因子：
9.9
作者：
通讯作者：
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DOI：
10.1073/pnas.0337542100
发表时间：
2003-02-18
影响因子：
11.1
作者：
Gust, B;Challis, GL;Chater, KF
通讯作者：
Chater, KF