Controlling electron transfer in acyl-CoA oxidases and dehydrogenases
Controlling electron transfer in acyl-CoA oxidases and dehydrogenases
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DOI：
10.1074/jbc.m603405200
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发表时间：
2006-10-13
影响因子：
4.8
通讯作者：
Henriksen, Anette
中科院分区：
文献类型：
--
作者：
Mackenzie, Jenny;Pedersen, Lise;Henriksen, Anette
植物产生一种独特的过氧体短链特异的酰基辅酶A氧化酶(ACX4)，用于脂肪的β-氧化。短链特异性氧化酶与其他过氧化物体酰辅酶A氧化酶几乎没有相似之处，但与线粒体酰辅酶A脱氢酶有30%的序列相似性。通过比较活性部位结合和不结合底物类似物的短链特异拟南芥ACX4的结构与已知的酰基辅酶A氧化酶和脱氢酶结构，有两个生化特征与结构特性有关：(I)溶剂可及的酰基结合口袋不是氧反应所必需的，(Ii)低聚状态在底物口袋结构中起作用，但与氧反应不相关。这些结构表明，酰基辅酶A氧化酶可能通过结构延伸阻断脱氢酶底物的相互作用部位，从而包裹电子转移到分子氧中。观察到与黄素腺嘌呤二核苷酸N5和C4a原子相邻的一个小结合口袋可以增加黄素腺嘌呤二核苷酸与O-2之间的生产性相遇的次数。
Plants produce a unique peroxisomal short chain-specific acyl-CoA oxidase (ACX4) for beta-oxidation of lipids. The short chain-specific oxidase has little resemblance to other peroxisomal acyl-CoA oxidases but has an similar to 30% sequence identity to mitochondrial acyl-CoA dehydrogenases. Two biochemical features have been linked to structural properties by comparing the structures of short chain-specific Arabidopsis thaliana ACX4 with and without a substrate analogue bound in the active site to known acyl-CoA oxidases and dehydrogenase structures: (i) a solvent-accessible acyl binding pocket is not required for oxygen reactivity, and (ii) the oligomeric state plays a role in substrate pocket architecture but is not linked to oxygen reactivity. The structures indicate that the acyl-CoA oxidases may encapsulate the electrons for transfer to molecular oxygen by blocking the dehydrogenase substrate interaction site with structural extensions. A small binding pocket observed adjoining the flavin adenine dinucleotide N5 and C4a atoms could increase the number of productive encounters between flavin adenine dinucleotide and O-2.