Protein misfolding is the molecular mechanism underlying MCADD identified in newborn screening.
Protein misfolding is the molecular mechanism underlying MCADD identified in newborn screening.
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DOI：
10.1093/hmg/ddp079
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发表时间：
2009-05-01
影响因子：
3.5
通讯作者：
Muntau AC
中科院分区：
文献类型：
--
作者：
Maier EM;Gersting SW;Kemter KF;Jank JM;Reindl M;Messing DD;Truger MS;Sommerhoff CP;Muntau AC
中链酰基辅酶a脱氢酶缺乏症（MCADD）的新生儿筛查（NBS）显示出比先前估计的更高的出生患病率和基因型变异性，包括ACADM基因中许多新的错义突变。平均而言，这些突变与较温和的生化表型相关，提出了有关其致病相关性的问题。在本研究中，我们分析了在NBS中发现的10个ACADM突变（A27V、Y42H、Y133H、R181C、R223G、D241G、K304E、R309K、I331T和R388S）对相应蛋白构象、稳定性和酶动力学的影响。通过共同过表达GroESL部分或全部挽救聚集表明蛋白质错误折叠。所有变异的热展开加速，以及大多数变异的蛋白水解稳定性下降和热失活加速证实了这一点。催化功能从高残留活性到显著降低活性或底物亲和力不等。突变映射到蛋白质的β-结构域，容易导致严重的不稳定。受影响的氨基酸残基的硅结构分析揭示了参与功能相关的网络。综上所述，我们的结果证实了蛋白质错误折叠和功能丧失是MCADD的共同分子基础的假设。此外，在所有分析的变异中，相当大的结构改变并不支持在NBS中发现的新突变比在临床确定的患者中检测到的突变具有更低的代谢失代偿风险的观点。最后，对ACADM错义突变如何导致MCAD功能丧失的详细了解可能为风险评估和患者咨询提供指导，并在未来可能有助于描述新的药理策略。
Newborn screening (NBS) for medium-chain acyl-CoA dehydrogenase deficiency (MCADD) revealed a higher birth prevalence and genotypic variability than previously estimated, including numerous novel missense mutations in the ACADM gene. On average, these mutations are associated with milder biochemical phenotypes raising the question about their pathogenic relevance. In this study, we analyzed the impact of 10 ACADM mutations identified in NBS (A27V, Y42H, Y133H, R181C, R223G, D241G, K304E, R309K, I331T and R388S) on conformation, stability and enzyme kinetics of the corresponding proteins. Partial to total rescue of aggregation by co-overexpression of GroESL indicated protein misfolding. This was confirmed by accelerated thermal unfolding in all variants, as well as decreased proteolytic stability and accelerated thermal inactivation in most variants. Catalytic function varied from high residual activity to markedly decreased activity or substrate affinity. Mutations mapping to the β-domain of the protein predisposed to severe destabilization. In silico structural analyses of the affected amino acid residues revealed involvement in functionally relevant networks. Taken together, our results substantiate the hypothesis of protein misfolding with loss-of-function being the common molecular basis in MCADD. Moreover, considerable structural alterations in all analyzed variants do not support the view that novel mutations found in NBS bear a lower risk of metabolic decompensation than that associated with mutations detected in clinically ascertained patients. Finally, the detailed insight into how ACADM missense mutations induce loss of MCAD function may provide guidance for risk assessment and counseling of patients, and in future may assist delineation of novel pharmacological strategies.
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影响因子：
168.9
作者：
Levy, Harvey L.;Milanowski, Andrzej;Dorenbaum, Alex
通讯作者：
Dorenbaum, Alex
DOI：
10.1016/0925-4439(93)90068-c
发表时间：
1993-10-20
期刊：
BIOCHIMICA ET BIOPHYSICA ACTA
影响因子：
--
作者：
BROSS, P;ANDRESEN, BS;GREGERSEN, N
通讯作者：
GREGERSEN, N
影响因子：
2.9
作者：
Nandy, A;Kieweg, V;Ghisla, S
通讯作者：
Ghisla, S
影响因子：
9.8
作者：
Gersting, Soren W.;Kemter, Kristina F.;Muntau, Ania C.
通讯作者：
Muntau, Ania C.
影响因子：
2
作者：
Nichols, Matthew J.;Saavedra-Matiz, Carlos A.;Caggana, Michele
通讯作者：
Caggana, Michele