The cobY gene of the archaeon Halobacterium sp. strain NRC-1 is required for de novo cobamide synthesis.
The cobY gene of the archaeon Halobacterium sp. strain NRC-1 is required for de novo cobamide synthesis.
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古细菌盐杆菌属的 cobY 基因。
DOI：
10.1128/jb.185.1.311-316.2003
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发表时间：
2003
影响因子：
3.2
通讯作者：
Escalante-Semerena,JC
中科院分区：
文献类型：
--
作者：
Woodson,JD;Peck,RF;Krebs,MP;Escalante-Semerena,JC
极端嗜盐古菌Halobacterium sp.突变体的遗传和营养分析。菌株NRC-1显示开放阅读框（ORF）Vng 1581 C编码具有三磷酸核苷：腺苷酰胺-磷酸核苷酸转移酶酶活性蛋白质。这种活性以前与产甲烷古菌Methanobacterium thermoautotrophicum菌株ΔH的cobY基因有关，但没有证据表明这种蛋白质直接参与古菌中的钴酰胺生物合成。嗜盐菌的计算机分析。菌株NRC-1 ORF Vng 1581 C基因和M.热自养菌ΔH株编码蛋白的氨基酸序列同源性为35%，相似性为48%。一株嗜盐菌（Halobacterium sp.）携带cobY基因的无效等位基因的菌株NRC-1是cobinamide-GDP的营养缺陷型，cobinamide-GDP是已知的cobamide生物合成后期步骤的中间产物。当将野生型等位基因ofcobY引入突变菌株中时，对cobinamide-GDP的营养缺陷型需求得到了纠正，表明缺乏cobY功能是在该古菌中观察到的钴酰胺生物合成受阻的唯一原因。研究还表明，盐杆菌属（Halobacterium sp.）菌株NRC-1具有高亲和性的类咕啉转运系统，并且该古菌可以在需氧生长条件下从头合成钴酰胺。据我们所知，这是第一次对古细菌中钴胺素生物合成突变体进行遗传和营养分析。
Genetic and nutritional analyses of mutants of the extremely halophilic archaeonHalobacteriumsp. strain NRC-1 showed that open reading frame (ORF) Vng1581C encodes a protein with nucleoside triphosphate:adenosylcobinamide-phosphate nucleotidyltransferase enzyme activity. This activity was previously associated with thecobYgene of the methanogenic archaeonMethanobacterium thermoautotrophicumstrain ΔH, but no evidence was obtained to demonstrate the direct involvement of this protein in cobamide biosynthesis in archaea. Computer analysis of theHalobacteriumsp. strain NRC-1 ORF Vng1581C gene and thecobYgene ofM. thermoautotrophicumstrain ΔH showed the primary amino acid sequence of the proteins encoded by these two genes to be 35% identical and 48% similar. A strain ofHalobacteriumsp. strain NRC-1 carrying a null allele of thecobYgene was auxotrophic for cobinamide-GDP, a known intermediate of the late steps of cobamide biosynthesis. The auxotrophic requirement for cobinamide-GDP was corrected when a wild-type allele ofcobYwas introduced into the mutant strain, demonstrating that the lack ofcobYfunction was solely responsible for the observed block in cobamide biosynthesis in this archaeon. The data also show thatHalobacteriumsp. strain NRC-1 possesses a high-affinity transport system for corrinoids and that this archaeon can synthesize cobamides de novo under aerobic growth conditions. To the best of our knowledge this is the first genetic and nutritional analysis of cobalamin biosynthetic mutants in archaea.