Isovaleryl-CoA(coenzyme A)dehydrogenase(IVD)plays a pivotal role in the catabolism of leucine,converting isovaleryl-CoA to 3-methylcrotonyl-CoA.Dysfunction of IVD is linked to isovaleric acidemia(IVA),a rare metabolic...Isovaleryl-CoA(coenzyme A)dehydrogenase(IVD)plays a pivotal role in the catabolism of leucine,converting isovaleryl-CoA to 3-methylcrotonyl-CoA.Dysfunction of IVD is linked to isovaleric acidemia(IVA),a rare metabolic disorder characterized by the accumulation of toxic metabolites.In this study,we present the cryo-electron microscopy structures of human IVD,resolved both in its apo form and in complex with its substrates,isovaleryl-CoA and butyryl-CoA.Our findings reveal a tetrameric architecture with distinct substrate-binding pockets that facilitate the enzyme’s preference for short branched-chain acyl-CoAs.Key residues involved in FAD binding and substrate interaction were identified,elucidating the catalytic mechanism of IVD.Additionally,we investigated the impact of various disease-associated hotspot mutations derived from different regions,demonstrating their effects on enzyme stability and activity.Notably,mutations such as A314V,S281G/F382V,and E411K resulted in substantial loss of function,while others exhibited milder effects,which is consistent with our structural analyses.These insights enhance our understanding of IVD’s enzymatic properties and provide a foundation for developing targeted therapies for IVA.展开更多
目的对4例经由新生儿筛查发现的不同临床类型的3-甲基巴豆酰辅酶A羧化酶缺乏症(3-methylcrotonyl-coenzyme A carboxylase deficiency,MCCD)患儿,用尿气相色谱质谱和基因分析证实其诊断。方法对新生儿筛查中C4DC+C5OH>0.6μmol/L的...目的对4例经由新生儿筛查发现的不同临床类型的3-甲基巴豆酰辅酶A羧化酶缺乏症(3-methylcrotonyl-coenzyme A carboxylase deficiency,MCCD)患儿,用尿气相色谱质谱和基因分析证实其诊断。方法对新生儿筛查中C4DC+C5OH>0.6μmol/L的新生儿召回复查,同时检测其母亲的C4DC+C5OH浓度。用尿气相色谱质谱分析对MCCD疑诊病例进行临床诊断,再通过基因分析进一步证实。结果通过基因诊断确诊MCCD 3例,包括MCCD患儿1例,父源性MCCD 1例,母源性MCCD 1例。另有1例临床诊断的MCCD患儿经基因检测仅找到1个致病位点。结论对新生儿筛查中发现的C4DC+C5OH增高的新生儿家系(包括母亲和父亲)应行MS/MS检测。疑似MCCD患者基因检测仅发现1个致病位点时不要轻易否定MCCD的诊断,建议定期随访。展开更多
基金supported by the National Key Research and Development Program of China(2022YFC2703100 and 2023YFC3605504)the Chinese Academy of Medical Sciences Initiative for Innovative Medicine(2021-I2M-1-003)+1 种基金the National High Level Hospital Clinical Research Funding(2022-PUMCH-D-002 and 2022-PUMCH-B-098)the National Natural Science Foundation of China(82225007,92149305,and 82030017).
文摘Isovaleryl-CoA(coenzyme A)dehydrogenase(IVD)plays a pivotal role in the catabolism of leucine,converting isovaleryl-CoA to 3-methylcrotonyl-CoA.Dysfunction of IVD is linked to isovaleric acidemia(IVA),a rare metabolic disorder characterized by the accumulation of toxic metabolites.In this study,we present the cryo-electron microscopy structures of human IVD,resolved both in its apo form and in complex with its substrates,isovaleryl-CoA and butyryl-CoA.Our findings reveal a tetrameric architecture with distinct substrate-binding pockets that facilitate the enzyme’s preference for short branched-chain acyl-CoAs.Key residues involved in FAD binding and substrate interaction were identified,elucidating the catalytic mechanism of IVD.Additionally,we investigated the impact of various disease-associated hotspot mutations derived from different regions,demonstrating their effects on enzyme stability and activity.Notably,mutations such as A314V,S281G/F382V,and E411K resulted in substantial loss of function,while others exhibited milder effects,which is consistent with our structural analyses.These insights enhance our understanding of IVD’s enzymatic properties and provide a foundation for developing targeted therapies for IVA.
