scholarly journals PLP1 Mutations in Patients with Multiple Sclerosis: Identification of a New Mutation and Potential Pathogenicity of the Mutations

2018 ◽  
Vol 7 (10) ◽  
pp. 342 ◽  
Author(s):  
Nancy Cloake ◽  
Jun Yan ◽  
Atefeh Aminian ◽  
Michael Pender ◽  
Judith Greer
Keyword(s):  
Multiple Sclerosis ◽  
Clinical Symptoms ◽  
Point Mutations ◽  
Human Leukocyte ◽  
In Silico Analysis ◽  
Proteolipid Protein ◽  
Wild Type ◽  
Exon 2 ◽  
Mutant Proteins ◽  
The Unfolded Protein Response

PLP1 is located on the X-chromosome and encodes myelin proteolipid protein (PLP), the most abundant protein in central nervous system myelin. Generally, point mutations in PLP1 result in X-linked dysmyelinating disorders, such as Pelizaeus-Merzbacher disease (PMD) or spastic paraplegia type 2 (SPG2). However, several case studies have identified patients with missense point mutations in PLP1 and clinical symptoms and signs compatible with a diagnosis of multiple sclerosis (MS). To investigate if PLP1 mutations occur relatively frequently in MS, we sequenced the coding regions of PLP1 in 22 female MS patients who had developed disease after the age of 40 and in 42 healthy women, and identified a missense mutation in exon 2 of PLP1 resulting in a Leu30Val mutation in the protein in one of the MS patients. mCherry-tagged plasmids containing wild type or mutant PLP1 sequences of PLP, including two known PMD/SPG2-related mutations as positive controls, were constructed and transfected into Cos-7 cells. In comparison with cells transfected with wild type PLP1, all mutations caused significant accumulation of PLP in the endoplasmic reticulum of the cells and induction of the unfolded protein response—a mechanism that leads to apoptosis of cells expressing mutant proteins. Additionally, in silico analysis of the binding of peptides containing the Leu30Val mutation to the human leukocyte antigen (HLA) molecules carried by the patient harboring this mutation suggested that the mutation could produce several novel immunogenic epitopes in this patient. These results support the idea that mutations in myelin-related genes could contribute to the development of MS in a small proportion of patients.

scholarly journals Analysis of phage-resistant mechanisms inStaphylococcus aureusSA003 reveals a different binding mechanism for the closely related Twort-like phages ϕSA012 and ϕSA039

2018 ◽  
Author(s):  
Aa Haeruman Azam ◽  
Fumiya Hoshiga ◽  
Ippei Takeuchi ◽  
Kazuhiko Miyanaga ◽  
Yasunori Tanji
Keyword(s):  
Teichoic Acid ◽  
Point Mutations ◽  
In Silico Analysis ◽  
Close Relative ◽  
Phenotypic Change ◽  
Missense Mutations ◽  
Wild Type ◽  
Wall Teichoic Acid ◽  
Whole Genome Analysis ◽  
Specific Phage

ABSTRACTWe have previously generated strains ofStaphylococcus aureusSA003 resistant to its specific phage ϕSA012 through long-term coevolution experiment. However, the DNA mutations responsible for the phenotypic change of phage resistance are unknown. Whole-genome analysis revealed six genes that acquired unique point mutations: five missense mutations and one nonsense mutation. Moreover, one deletion, 1.779-bp, resulted in the deletion of the genes encoding glycosyltransferase, TarS, and iron-sulfure repair protein, ScdA. The deletion occurred from the second round of coculture (SA003R2) and remained through the last round. The ϕSA012 infection toward SA003R2 had decreased to 79.77±7.50% according to plating efficiency. Complementation of the phage-resistant strain by the wild-type allele showed two mutated host genes were linked to the inhibition of post-adsorption, and five genes were linked to phage adsorption of ϕSA012. Unlike ϕSA012, infection by ϕSA039, a close relative of ϕSA012, onto SA003R2 was impaired drastically. Complementation of SA003R2 by wild-typetarSrestores the infectivity of ϕSA039. Thus, we concluded that ϕSA039 requires β-GlcNAc in Wall Teichoic Acid (WTA) for its binding. In silico analysis of the ϕSA039 genome revealed that several proteins in the tail and baseplate region were different from ϕSA012; notably the partial deletion oforf96of ϕSA039, a homolog oforf99of ϕSA012.Orf100of ϕSA039, a homolog ofOrf103of ϕSA012, a previously reported receptor binding protein (RBP), had low similarity (86%) to that of ϕSA012. The difference in tail and baseplate proteins might be the factor for specificity difference between ϕSA012 and ϕSA039.

scholarly journals The Wiskott-Aldrich syndrome and X-linked congenital thrombocytopenia are caused by mutations of the same gene

Blood ◽  
1995 ◽  
Vol 86 (10) ◽  
pp. 3797-3804 ◽  
Author(s):  
Q Zhu ◽  
M Zhang ◽  
RM Blaese ◽  
JM Derry ◽  
A Junker ◽  
...  
Keyword(s):  
Clinical Symptoms ◽  
Point Mutations ◽  
Gene Mutations ◽  
Exon Skipping ◽  
Splice Site Mutation ◽  
Missense Mutations ◽  
Site Mutation ◽  
Exon 2 ◽  
Wiskott Aldrich Syndrome ◽  
Was Gene

The Wiskott-Aldrich syndrome (WAS) is an X-linked recessive disorder characterized by thrombocytopenia, small platelets, eczema, recurrent infections, and immunodeficiency. Besides the classic WAS phenotype, there is a group of patients with congenital X-linked thrombocytopenia (XLT) who have small platelets but only transient eczema, if any, and minimal immune deficiency. Because the gene responsible for WAS has been sequenced, it was possible to correlate the WAS phenotypes with WAS gene mutations. Using a fingerprinting screening technique, we determined the approximate location of the mutation in 13 unrelated WAS patients with mild to severe clinical symptoms. Direct sequence analysis of cDNA and genomic DNA obtained from patient-derived cell lines showed 12 unique mutations distributed throughout the WAS gene, including insertions, deletions, and point mutations resulting in amino acid substitutions, termination, exon skipping, or splicing defects. Of 4 unrelated patients with the XLT phenotype, 3 had missense mutations affecting exon 2 and 1 had a splice-site mutation affecting exon 9. Patients with classic WAS had more complex mutations, resulting in termination codons, frameshift, and early termination. These findings provide direct evidence that XLT and WAS are caused by mutations of the same gene and suggest that severe clinical phenotypes are associated with complex mutations.

scholarly journals S279 Point Mutations in Candida albicans Sterol 14-α Demethylase (CYP51) ReduceIn VitroInhibition by Fluconazole

2012 ◽  
Vol 56 (4) ◽  
pp. 2099-2107 ◽  
Author(s):  
Andrew G. S. Warrilow ◽  
Jonathan G. L. Mullins ◽  
Claire M. Hull ◽  
Josie E. Parker ◽  
David C. Lamb ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Point Mutations ◽  
Triazole Ring ◽  
Wild Type ◽  
Protein Activity ◽  
Content Type ◽  
Mutant Proteins ◽  
Type Protein ◽  
Wild Type Protein ◽  
Binding Spectra

ABSTRACTThe effects of S279F and S279Y point mutations inCandida albicansCYP51 (CaCYP51) on protein activity and on substrate (lanosterol) and azole antifungal binding were investigated. Both S279F and S279Y mutants bound lanosterol with 2-fold increased affinities (Ks, 7.1 and 8.0 μM, respectively) compared to the wild-type CaCYP51 protein (Ks, 13.5 μM). The S279F and S279Y mutants and the wild-type CaCYP51 protein bound fluconazole, voriconazole, and itraconazole tightly, producing typical type II binding spectra. However, the S279F and S279Y mutants had 4- to 5-fold lower affinities for fluconazole, 3.5-fold lower affinities for voriconazole, and 3.5- to 4-fold lower affinities for itraconazole than the wild-type CaCYP51 protein. The S279F and S279Y mutants gave 2.3- and 2.8-fold higher 50% inhibitory concentrations (IC50s) for fluconazole in a CYP51 reconstitution assay than the wild-type protein did. The increased fluconazole resistance conferred by the S279F and S279Y point mutations appeared to be mediated through a combination of a higher affinity for substrate and a lower affinity for fluconazole. In addition, lanosterol displaced fluconazole from the S279F and S279Y mutants but not from the wild-type protein. Molecular modeling of the wild-type protein indicated that the oxygen atom of S507 interacts with the second triazole ring of fluconazole, assisting in orientating fluconazole so that a more favorable binding conformation to heme is achieved. In contrast, in the two S279 mutant proteins, this S507-fluconazole interaction is absent, providing an explanation for the higherKdvalues observed.

scholarly journals Mutations in the N- and C-terminal Tails of Potato Carboxypeptidase Inhibitor Influence Its Oxidative Refolding Process at the Reshuffling Stage

2001 ◽  
Vol 276 (15) ◽  
pp. 11683-11690 ◽  
Author(s):  
Gabriela Venhudová ◽  
Francesc Canals ◽  
Enrique Querol ◽  
Francesc X. Aviles
Keyword(s):  
Noncovalent Interactions ◽  
Point Mutations ◽  
Second Phase ◽  
Wild Type ◽  
Lower Efficiency ◽  
Native Form ◽  
Mutant Proteins ◽  
Oxidative Refolding ◽  
Stable Species ◽  
Carboxypeptidase Inhibitor

A comparative study of the oxidative refolding for nine selected potato carboxypeptidase inhibitor (PCI) mutants was carried out using the disulfide quenching approach. The mutations were performed at the N- and C-terminal tails of PCI outside its disulfide stabilized central core. The differences between the refolding of wild type and mutant proteins were observed in the second phase of the refolding process, the reshuffling of disulfide bridges, although the first phase, nonspecific packing, was not greatly affected by the mutations. Point mutations at the C-tail or deletion of up to three C-terminal residues of PCI resulted in a lower efficiency of the reshuffling process. In the case of the mutants lacking five N-terminal or four or five C-terminal residues, no “native-like” form was observed after the refolding process. On the other hand, the double mutant G35P/P36G did not attain a native-like form either, although one slightly more stable species was observed after being submitted to refolding. The disulfide pairing of this species is different from that of the wtPCI native form. The differences between the refolding process of wild type and mutant forms are interpreted in the light of the new view of protein folding. The results of the present study support the hypothesis that the refolding of this small disulfide-rich protein, and others, is driven by noncovalent interactions at the reshuffling stage. It is also shown that the interactions established between the N- and C-tail residues and the core of PCI are important for the proper refolding of the protein.

scholarly journals Structural and functional effects of hereditary hemolytic anemia-associated point mutations in the alpha spectrin tetramer site

Blood ◽  
2008 ◽  
Vol 111 (12) ◽  
pp. 5712-5720 ◽  
Author(s):  
Massimiliano Gaetani ◽  
Sara Mootien ◽  
Sandra Harper ◽  
Patrick G. Gallagher ◽  
David W. Speicher
Keyword(s):  
Clinical Symptoms ◽  
Point Mutations ◽  
Titration Calorimetry ◽  
Missense Mutations ◽  
Binding Affinities ◽  
Wild Type ◽  
Tetramer Binding ◽  
Structural And Functional Properties ◽  
Recombinant Peptides ◽  
Self Association

Abstract The most common hereditary elliptocytosis (HE) and hereditary pyropoikilocytosis (HPP) mutations are α-spectrin missense mutations in the dimer-tetramer self-association site. In this study, we systematically compared structural and functional properties of the 14 known HE/HPP mutations located in the α-spectrin tetramer binding site. All mutant α-spectrin recombinant peptides were well folded, stable structures, with only the R34W mutant exhibiting a slight structural destabilization. In contrast, binding affinities measured by isothermal titration calorimetry were greatly variable, ranging from no detectable binding observed for I24S, R28C, R28H, R28S, and R45S to approximately wild-type binding for R34W and K48R. Binding affinities for the other 7 mutants were reduced by approximately 10- to 100-fold relative to wild-type binding. Some sites, such as R28, were hot spots that were very sensitive to even relatively conservative substitutions, whereas other sites were only moderately perturbed by nonconservative substitutions. The R34W and K48R mutations were particularly intriguing mutations that apparently either destabilize tetramers through mechanisms not probed by the univalent tetramer binding assay or represent polymorphisms rather than the pathogenic mutations responsible for observed clinical symptoms. All α0 HE/HPP mutations studied here appear to exert their destabilizing effects through molecular recognition rather than structural mechanisms.

Increasing the redox potential of isoform 1 of yeast cytochrome c through the modification of select haem interactions

2002 ◽  
Vol 362 (2) ◽  
pp. 281-287 ◽  
Author(s):  
C. Marc LETT ◽  
J. Guy GUILLEMETTE
Keyword(s):  
Cytochrome C ◽  
Redox Potential ◽  
Point Mutations ◽  
Cd Spectroscopy ◽  
Wild Type ◽  
Mutant Proteins ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Biophysical Studies ◽  
Cytochromes C

The oxidation—reduction potential of eukaryotic cytochromes c varies very little from species to species. We have introduced point mutations into isoform 1 of yeast cytochrome c (iso-1-cytochrome c) to selectively engineer a protein with a higher redox potential. Of the ten different mutant proteins generated for the present investigation Y67R, Y67K and W59H were found to be non-functional. Three other mutant proteins, L32M, L32T and T49K, were functional, but too unstable for biophysical studies. Mutant cytochromes c K79S, K79T, Y48H and Y48K were purified and characterized. The Y48K mutant is the only one that exhibits a significant increase of +117mV in redox potential compared with the wild-type protein while still supporting oxidative phosphorylation invivo. Low temperature difference spectroscopy confirmed the formation of the holoprotein, while adsorption and CD spectroscopy reveal perturbations in the structure of Y48K iso-1-cytochrome c.

scholarly journals In-Silico Design of Peptides for Inhibition of HLA-A*03-KLIETYFSK Complex as a New Drug Design for Treatment of Multiples Sclerosis Disease

2021 ◽  
Author(s):  
Zahra Ghobadi ◽  
karim mahnam ◽  
Mostafa Shakhsi-Niaei
Keyword(s):  
Multiple Sclerosis ◽  
Binding Affinity ◽  
Cytotoxic T Cells ◽  
Human Leukocyte ◽  
Hla Class I ◽  
Proteolipid Protein ◽  
Chronic Inflammatory Disease ◽  
Class I ◽  
Cytotoxic T Cell ◽  
Almost All

Abstract Multiple sclerosis is recognized as a chronic inflammatory disease. Human leukocyte antigen (HLA) plays an important role in initiating adaptive immune responses. HLA class I is present in almost all nucleated cells and presents the cleaved endogenous peptide antigens to cytotoxic T cells. HLA-A*03 is one of the HLA class I alleles, which is reported as substantially related HLA to MS disease. In 2011, structure of the HLA-A*03 in complex was identified with an immunodominant proteolipid protein (PLP) epitope (KLIETYFSK). This complex has been reported as an important autoantigen-presenting complex in MS pathogenesis. In this study, new peptides were designed to bind to this complex that may prevent specific pathogenic cytotoxic T cell binding to this autoantigen-presenting complex and CNS demyelination. Herein, 14 new helical peptides containing 19 amino acids were designed and their structures were predicted using the PEP-FOLD server. Binding of each designed peptide to the mentioned complex was then performed. A mutation approach was used by the BeAtMuSiC server to improve binding affinity of the designed peptide. In each position, amino acid substitutions leading to an increase in binding affinity of the peptide to the mentioned complex were determined. Finally, the resulting complexes were simulated for 40 ns using AMBER18 software. The results revealed that out of 14 designed peptides, “WRYWWKDWAKQFRQFYRWF” peptide exhibited the highest affinity for binding to the mentioned complex. This peptide can be considered as a potential drug to control multiple sclerosis disease in patients carrying the HLA-A*03 allele.

Effects of single amino acid substitutions in the actin-binding site on the biological activity of bovine profilin I

1998 ◽  
Vol 111 (22) ◽  
pp. 3261-3273
Author(s):  
K. Schluter ◽  
M. Schleicher ◽  
B.M. Jockusch
Keyword(s):  
Binding Capacity ◽  
Point Mutations ◽  
Single Amino Acid ◽  
Actin Binding ◽  
Wild Type ◽  
Mutant Proteins ◽  
Surface Areas ◽  
Order Of Magnitude ◽  
Colony Surface

For a detailed analysis of the profilin-actin interaction, we designed several point mutations in bovine profilin I by computer modeling. The recombinant proteins were analyzed in vitro for their actin-binding properties. Mutant proteins with a putatively higher affinity for actin were produced by attempting to introduce an additional bond to actin. However, these mutants displayed a lower affinity for actin than wild-type profilin, suggesting that additional putative bonds created this way cannot increase profilin's affinity for actin. In contrast, mutants designed to have a reduced affinity for actin by eliminating profilin-actin bonds displayed the desired properties in viscosity assays, while their binding sites for poly(L)proline were still intact. The profilin mutant F59A, with an affinity for actin reduced by one order of magnitude as compared to wild-type profilin, was analyzed further in cells. When microinjected into fibroblasts, F59A colocalized with the endogenous profilin and actin in ruffling areas, suggesting that profilins are targeted to and tethered at these sites by ligands other than actin. Profilin null cells of Dictyostelium were transfected with bovine wild-type profilin I and F59A. Bovine profilin I, although expressed to only approximately 10% of the endogenous profilin level determined for wild-type Dictyostelium, caused a substantial rescue of the defects observed in profilin null amoebae, as seen by measuring the growth of colony surface areas and the percentage of polynucleated cells. The mutant protein was much less effective. These results emphasize the highly conserved biological function of profilins with low sequence homology, and correlate specifically their actin-binding capacity with cell motility and proliferation.

scholarly journals Hypomyelinating Leukodystrophy 15 (HLD15)-Associated Mutation of EPRS1 Leads to Its Polymeric Aggregation in Rab7-Positive Vesicle Structures, Inhibiting Oligodendroglial Cell Morphological Differentiation

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1074
Author(s):  
Sui Sawaguchi ◽  
Mizuki Goto ◽  
Yukino Kato ◽  
Marina Tanaka ◽  
Kenji Tago ◽  
...  
Keyword(s):  
Morphological Differentiation ◽  
Proteolipid Protein ◽  
Trna Synthetase ◽  
Structural Protein ◽  
Aminoacyl Trna Synthetase ◽  
Wild Type ◽  
Mutant Proteins ◽  
Trna Species ◽  
Pelizaeus Merzbacher Disease ◽  
Hypomyelinating Leukodystrophy

Pelizaeus–Merzbacher disease (PMD), also known as hypomyelinating leukodystrophy 1 (HLD1), is an X-linked recessive disease affecting in the central nervous system (CNS). The gene responsible for HLD1 encodes proteolipid protein 1 (plp1), which is the major myelin structural protein produced by oligodendroglial cells (oligodendrocytes). HLD15 is an autosomal recessive disease affecting the glutamyl-prolyl-aminoacyl-tRNA synthetase 1 (eprs1) gene, whose product, the EPRS1 protein, is a bifunctional aminoacyl-tRNA synthetase that is localized throughout cell bodies and that catalyzes the aminoacylation of glutamic acid and proline tRNA species. Here, we show that the HLD15-associated nonsense mutation of Arg339-to-Ter (R339X) localizes EPRS1 proteins as polymeric aggregates into Rab7-positive vesicle structures in mouse oligodendroglial FBD-102b cells. Wild-type proteins, in contrast, are distributed throughout the cell bodies. Expression of the R339X mutant proteins, but not the wild-type proteins, in cells induces strong signals regulating Rab7. Whereas cells expressing the wild-type proteins exhibited phenotypes with myelin web-like structures bearing processes following the induction of differentiation, cells expressing the R339X mutant proteins did not. These results indicate that HLD15-associated EPRS1 mutant proteins are localized in Rab7-positive vesicle structures where they modulate Rab7 regulatory signaling, inhibiting cell morphological differentiation. These findings may reveal some of the molecular and cellular pathological mechanisms underlying HLD15.

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