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- Ng, Bobby G, et al.
(författare)
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ALG1-CDG: Clinical and Molecular Characterization of 39 Unreported Patients.
- 2016
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Ingår i: Human Mutation. - : Hindawi Limited. - 1059-7794.
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Tidskriftsartikel (refereegranskat)abstract
- Congenital disorders of glycosylation (CDG) arise from pathogenic mutations in over one hundred genes leading to impaired protein or lipid glycosylation. ALG1 encodes a β1,4 mannosyltransferase that catalyzes the addition of the first of nine mannose moieties to form a dolichol-lipid linked oligosaccharide intermediate (DLO) required for proper N-linked glycosylation. ALG1 mutations cause a rare autosomal recessive disorder termed ALG1-CDG. To date thirteen mutations in eighteen patients from fourteen families have been described with varying degrees of clinical severity. We identified and characterized thirty-nine previously unreported cases of ALG1-CDG from thirty-two families and add twenty-six new mutations. Pathogenicity of each mutation was confirmed based on its inability to rescue impaired growth or hypoglycosylation of a standard biomarker in an alg1-deficient yeast strain. Using this approach we could not establish a rank order comparison of biomarker glycosylation and patient phenotype, but we identified mutations with a lethal outcome in the first two years of life. The recently identified protein-linked xeno-tetrasaccharide biomarker, NeuAc-Gal-GlcNAc2 , was seen in all twenty-seven patients tested. Our study triples the number of known patients and expands the molecular and clinical correlates of this disorder. This article is protected by copyright. All rights reserved.
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| 2. |
- Olsson, Pär A T, 1981-, et al.
(författare)
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All-atomic and coarse-grained molecular dynamics investigation of deformation in semi-crystalline lamellar polyethylene
- 2018
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Ingår i: Polymer. - : Elsevier Ltd. - 0032-3861 .- 1873-2291. ; 153, s. 305-316
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Tidskriftsartikel (refereegranskat)abstract
- In the present work we have performed classical molecular dynamics modelling to investigate the effects of different types of force-fields on the stress-strain and yielding behaviours in semi-crystalline lamellar stacked linear polyethylene. To this end, specifically the all-atomic optimized potential for liquid simulations (OPLS-AA) and the coarse-grained united-atom (UA) force-fields are used to simulate the yielding and tensile behaviour for the lamellar separation mode. Despite that the considered samples and their topologies are identical for both approaches, the results show that they predict widely different stress-strain and yielding behaviours. For all UA simulations we obtain oscillating stress-strain curves accompanied by repetitive chain transport to the amorphous region, along with substantial chain slip and crystal reorientation. For the OPLS-AA modelling primarily cavitation formation is observed, with small amounts of chain slip to reorient the crystal such that the chains align in the tensile direction. This force-field dependence is rooted in the lack of explicit H-H and C-H repulsion in the UA approach, which gives rise to underestimated ideal critical resolved shear stress. The computed critical resolved shear stress for the OPLS-AA approach is in good agreement with density functional theory calculations and the yielding mechanisms resemble those of the lamellar separation mode. The disparate energy and shear stress barriers for chain slip of the different models can be interpreted as differently predicted intrinsic activation rates for the mechanism, which ultimately are responsible for the observed diverse responses of the two modelling approaches. © 2018 Elsevier Ltd
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