TY - JOUR
T1 - Unveiling the unfolding pathway of f5f8d disorder-associated d81h/v100d mutant of mcfd2 via multiple molecular dynamics simulations
AU - Hamza, Adel
AU - Wei, Ning Ning
AU - Johnson-Scalise, Trudy
AU - Naftolin, Frederick
AU - Cho, Hoon
AU - Zhan, Chang Guo
N1 - Funding Information:
This work was supported in part by the NIH (grant R01 DA025100 to C.-G. Zhan).
PY - 2012/2
Y1 - 2012/2
N2 - Combined factor deficiency (F5F8D) is a rare autosomal recessive disorder caused by mutations in the LMAN1 or MCFD2 genes. It has been proposed that this pathogenic process occurs via a multi-step pathway involving metal loss, EF-hand-Ca2+ dissociation and assembly of misfolded MCFD2-LMAN1 complex. Here, we have investigated the solution conformations of the MCFD2(D81H, V100D) protein mutant through extensive molecular dynamics (MD) simulations. The V100D, one of the many MCFD2 mutations known to be associated to F5F8D, is difficult to be reconciled with the pathway model because it is located far from the metal sites and the MCFD2/LMAN1 interface. Consequently, an inspection of all the steps involved in D81H/V100D MCFD2 misfolding is expected to provide hints in the understanding of the molecular basis of the disease. A comparison with parallel studies carried out for the Wild-Type (WT) MCFD2 pointed out that the mutation decreases the affinity of the protein for the Ca2+ ion. Multiple explicit solvents MD simulations (50 ns) performed on the two proteins revealed that in the WT protein, stable H-bond network and compact hydrophobic core region are created thus confirming a pivotal role of this region in driving the biophysical properties of the entire protein. In fact it is shown that the V100D mutation, although located far away the EF-hand domain, may induce subtle modification in the structural core of MCFD2 leading to the loosening of metal binding and to the formation of metastable intermediate states along the unfolding pathway. The native-like hydrophobic cluster formed near the V100 residue in the wild-type protein is disrupted by the negatively charged Asparagine residue. Furthermore, the presence of the D81H mutation in the EF-1 hand domain may also increase the protein unfolding rate and consequently prevent the formation of the MCFD2-LMAN1 complex. The detailed structural insights obtained from our large-scale simulations complement the clinical features and offer useful insights into the mechanism behind MCFD2 protein misfolding.
AB - Combined factor deficiency (F5F8D) is a rare autosomal recessive disorder caused by mutations in the LMAN1 or MCFD2 genes. It has been proposed that this pathogenic process occurs via a multi-step pathway involving metal loss, EF-hand-Ca2+ dissociation and assembly of misfolded MCFD2-LMAN1 complex. Here, we have investigated the solution conformations of the MCFD2(D81H, V100D) protein mutant through extensive molecular dynamics (MD) simulations. The V100D, one of the many MCFD2 mutations known to be associated to F5F8D, is difficult to be reconciled with the pathway model because it is located far from the metal sites and the MCFD2/LMAN1 interface. Consequently, an inspection of all the steps involved in D81H/V100D MCFD2 misfolding is expected to provide hints in the understanding of the molecular basis of the disease. A comparison with parallel studies carried out for the Wild-Type (WT) MCFD2 pointed out that the mutation decreases the affinity of the protein for the Ca2+ ion. Multiple explicit solvents MD simulations (50 ns) performed on the two proteins revealed that in the WT protein, stable H-bond network and compact hydrophobic core region are created thus confirming a pivotal role of this region in driving the biophysical properties of the entire protein. In fact it is shown that the V100D mutation, although located far away the EF-hand domain, may induce subtle modification in the structural core of MCFD2 leading to the loosening of metal binding and to the formation of metastable intermediate states along the unfolding pathway. The native-like hydrophobic cluster formed near the V100 residue in the wild-type protein is disrupted by the negatively charged Asparagine residue. Furthermore, the presence of the D81H mutation in the EF-1 hand domain may also increase the protein unfolding rate and consequently prevent the formation of the MCFD2-LMAN1 complex. The detailed structural insights obtained from our large-scale simulations complement the clinical features and offer useful insights into the mechanism behind MCFD2 protein misfolding.
KW - F5F8D
KW - LMAN1
KW - MCFD2
KW - Misfolding
KW - Molecular Dynamics
KW - Mutations
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U2 - 10.1080/07391102.2012.10507410
DO - 10.1080/07391102.2012.10507410
M3 - Article
C2 - 22208273
AN - SCOPUS:84855175981
SN - 0739-1102
VL - 29
SP - 699
EP - 714
JO - Journal of Biomolecular Structure and Dynamics
JF - Journal of Biomolecular Structure and Dynamics
IS - 4
ER -