scholarly journals Structural basis for a complex I mutation that blocks pathological ROS production

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Zhan Yin ◽  
Nils Burger ◽  
Duvaraka Kula-Alwar ◽  
Dunja Aksentijević ◽  
Hannah R. Bridges ◽  
...  
Keyword(s):  
Point Mutation ◽  
Complex I ◽  
Structural Changes ◽  
Ischemia Reperfusion ◽  
Single Point ◽  
Structural Basis ◽  
Single Point Mutation ◽  
Ros Production

AbstractMitochondrial complex I is central to the pathological reactive oxygen species (ROS) production that underlies cardiac ischemia–reperfusion (IR) injury. ND6-P25L mice are homoplasmic for a disease-causing mtDNA point mutation encoding the P25L substitution in the ND6 subunit of complex I. The cryo-EM structure of ND6-P25L complex I revealed subtle structural changes that facilitate rapid conversion to the “deactive” state, usually formed only after prolonged inactivity. Despite its tendency to adopt the “deactive” state, the mutant complex is fully active for NADH oxidation, but cannot generate ROS by reverse electron transfer (RET). ND6-P25L mitochondria function normally, except for their lack of RET ROS production, and ND6-P25L mice are protected against cardiac IR injury in vivo. Thus, this single point mutation in complex I, which does not affect oxidative phosphorylation but renders the complex unable to catalyse RET, demonstrates the pathological role of ROS production by RET during IR injury.

scholarly journals Single point mutation in adeno-associated viral vectors -DJ capsid leads to improvement for gene delivery in vivo

2016 ◽  
Vol 16 (1) ◽  
Author(s):  
Yingying Mao ◽  
Xuejun Wang ◽  
Renhe Yan ◽  
Wei Hu ◽  
Andrew Li ◽  
...  
Keyword(s):  
Gene Delivery ◽  
Point Mutation ◽  
Viral Vectors ◽  
Single Point ◽  
Single Point Mutation

scholarly journals The Role of Chemically Modified DNA in Discrimination of Single-Point Mutation through Plasmon-Based Colorimetric Assays

2018 ◽  
Vol 1 (7) ◽  
pp. 3741-3746 ◽  
Author(s):  
María Sanromán-Iglesias ◽  
Charles H. Lawrie ◽  
Luis M. Liz-Marzán ◽  
Marek Grzelczak
Keyword(s):  
Point Mutation ◽  
Single Point ◽  
Single Point Mutation ◽  
Chemically Modified ◽  
Modified Dna ◽  
Colorimetric Assays

Abstract 52: The Role of Kindlin-2 in Integrin Activation Depends on a Short C-Terminal Region

2012 ◽  
Vol 32 (suppl_1) ◽  
Author(s):  
Jamila Hirbawi ◽  
Kamila Bledzka ◽  
Yan Qing Ma ◽  
Jun Qin ◽  
Edward F Plow
Keyword(s):  
Amino Acids ◽  
Point Mutation ◽  
Single Point ◽  
Terminal Region ◽  
Membrane Receptors ◽  
Single Point Mutation ◽  
Loss Of Function ◽  
Integrin Activation ◽  
C Terminus

Integrins are heterodimeric cell membrane receptors that regulate cell adhesion, migration, and survival. The kindlins are known to be key regulators of integrin activation, the transition from a low affinity, default state to a high affinity state for ligand. This function depends on their binding, together with talin, to the cytoplasmic tails (CT) of the β subunit of integrins. Kindlins are FERM domain containing proteins, and it is its F3 (PTB) subdomain of the FERM that is the primary binding site for integrin β CT. At its very C-terminus, beyond the F3, is a short extension of 21 amino acids, K2 660-680, and we have focused on the role of this region in the co-activator function of kindlin-2 (K2). For this analysis, we performed PAC-1 (antibody to detect activated αIIbβ3 integrin) binding assays in CHO cells stably expressing integrin α IIb β 3 that were transiently transfected with talin head domain and K2 mutants. Expression levels of all proteins were verified to be similar by western blotting and FACS. Truncation of K2 at residue 660 essentially eliminated the co-activator function of K2. Deletion of smaller segments also reduced co-activator activity by 50% to 100%. Deletion of just the last two amino acids in the sequence, W 679 V 680 , resulted in a 50% reduction in co-activator activity and a single point mutation of Y 673 A also led to a 50% loss of function. A combination mutant consisting of the W 679 V 680 deletion and the Y 673 point mutation resulted in 100% loss of kindlin-2 co-activator activity. Pull-down experiments performed using GST tagged β 3 CT and CHO lysates transfected with GFP-kindlin-2 forms suggested that the C-terminal deletion did not disrupt binding to β 3 CT. This observation was corroborated by surface plasmon resonance studies in which the binding of full-length K2 and K2Δ666C (Δ666) was compared, and their K D values for immobilized β3 CT were found to be essentially the same. Overall, these data establish an important and unanticipated role of the carboxy-terminal region of kindlin-2 in its integrin co-activator function that is not dependent of its binding to integrin.

scholarly journals Structural effects of the highly protective V127 polymorphism on human prion protein

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Laszlo L. P. Hosszu ◽  
Rebecca Conners ◽  
Daljit Sangar ◽  
Mark Batchelor ◽  
Elizabeth B. Sawyer ◽  
...  
Keyword(s):  
Prion Protein ◽  
Prion Disease ◽  
Structural Changes ◽  
Prion Diseases ◽  
Single Point ◽  
Structural Basis ◽  
Single Point Mutation ◽  
Solution Dynamics ◽  
Human Prion Protein ◽  
Prion Transmission

AbstractPrion diseases, a group of incurable, lethal neurodegenerative disorders of mammals including humans, are caused by prions, assemblies of misfolded host prion protein (PrP). A single point mutation (G127V) in human PrP prevents prion disease, however the structural basis for its protective effect remains unknown. Here we show that the mutation alters and constrains the PrP backbone conformation preceding the PrP β-sheet, stabilising PrP dimer interactions by increasing intermolecular hydrogen bonding. It also markedly changes the solution dynamics of the β2-α2 loop, a region of PrP structure implicated in prion transmission and cross-species susceptibility. Both of these structural changes may affect access to protein conformers susceptible to prion formation and explain its profound effect on prion disease.

scholarly journals A single point mutation in TFIIA suppresses NC2 requirement in vivo

2000 ◽  
Vol 19 (4) ◽  
pp. 672-682 ◽  
Author(s):  
Jun Xie ◽  
Martine Collart ◽  
Marc Lemaire ◽  
Gertraud Stelzer ◽  
Michael Meisterernst
Keyword(s):  
Point Mutation ◽  
Single Point ◽  
Single Point Mutation

Turning around the electron flow in an uptake hydrogenase. EPR spectroscopy and in vivo activity of a designed mutant in HupSL from Nostoc punctiforme

2016 ◽  
Vol 9 (2) ◽  
pp. 581-594 ◽  
Author(s):  
Patrícia Raleiras ◽  
Namita Khanna ◽  
Hélder Miranda ◽  
Lívia S. Mészáros ◽  
Henning Krassen ◽  
...  
Keyword(s):  
Point Mutation ◽  
Epr Spectroscopy ◽  
Electron Flow ◽  
Single Point ◽  
Single Point Mutation ◽  
Uptake Hydrogenase ◽  
Nostoc Punctiforme

The uptake hydrogenase HupSL became a H2 producer in N. punctiforme after modifying the proximal FeS cluster with the single point mutation C12P.

Point mutation in acetolactate synthase confers sulfonylurea and imidazolinone herbicide resistance in spiny annual sow-thistle [Sonchus asper (L.) Hill]

2012 ◽  
Vol 92 (2) ◽  
pp. 303-309 ◽  
Author(s):  
Kee Woong Park ◽  
Judith M. Kolkman ◽  
Carol A. Mallory-Smith
Keyword(s):  
Amino Acid ◽  
Point Mutation ◽  
Herbicide Resistance ◽  
Single Point ◽  
Acetolactate Synthase ◽  
Amino Acid Sequences ◽  
Cross Resistance ◽  
Single Point Mutation ◽  
Sonchus Asper

Park, K. W., Kolkman, J. M. and Mallory-Smith, C. A. 2012. Point mutation in acetolactate synthase confers sulfonylurea and imidazolinone herbicide resistance in spiny annual sow-thistle [Sonchus asper (L.) Hill]. Can. J. Plant Sci. 92: 303–309. Suspected thifensulfuron resistant spiny annual sow-thistle was identified near Colfax, Washington, in two fields with a winter wheat and lentil rotation. Therefore, studies were conducted to examine resistance of spiny annual sow-thistle to thifensulfuron and cross-resistance to other acetolactate synthase inhibitors and to determine the physiological and molecular basis for herbicide resistance. Whole-plant bioassay confirmed that the biotype was highly resistant to the sulfonylurea (SU) herbicides, thifensulfuron, metsulfuron, and prosulfuron. The resistant (R) biotype was also highly resistant to the imidazolinone (IMI) herbicides, imazamox and imazethapyr. An in vivo acetolactate synthase (ALS) assay indicated that the concentrations of SU and IMI herbicides required for 50% inhibition (I50) were more than 10 times greater for R biotype compared with susceptible (S) biotype. Analysis of the nucleotide and predicted amino acid sequences for ALS genes demonstrated a single-point mutation from C to T at the als1 gene, conferring the substitution of the amino acid leucine for proline in the R biotype at position197. The results of this research indicate that the resistance of spiny annual sow-thistle to SU and IMI herbicides is due to on altered target site and caused by a point mutation in the als1 gene.

scholarly journals Mutation in Irf8 Gene (Irf8R294C) Impairs Type I IFN-Mediated Antiviral Immune Response by Murine pDCs

2021 ◽  
Vol 12 ◽  
Author(s):  
Annesa Das ◽  
Kuldeep Singh Chauhan ◽  
Himanshu Kumar ◽  
Prafullakumar Tailor
Keyword(s):  
Immune Response ◽  
Point Mutation ◽  
Single Point ◽  
Costimulatory Molecules ◽  
Type I Interferons ◽  
Single Point Mutation ◽  
Type I ◽  
Type I Ifn ◽  
Antiviral Immune Response

Plasmacytoid dendritic cells (pDCs) are the key producers of type I interferons (IFNs), thus playing a central role in initiating antiviral immune response. Besides robust type I IFN production, pDCs also act as antigen presenting cells post immunogenic stimulation. Transcription factor Irf8 is indispensable for the development of both pDC and cDC1 subset. However, the mechanism underlying the differential regulation by IRF8 in cDC1- and pDC-specific genomic architecture of developmental pathways still remains to be fully elucidated. Previous studies indicated that the Irf8R294C mutation specifically abrogates development of cDC1 without affecting that of pDC. In the present study using RNA-seq based approach, we have found that though the point mutation Irf8R294C did not affect pDC development, it led to defective type I IFN production, thus resulting in inefficient antiviral response. This observation unraveled the distinctive roles of IRF8 in these two subpopulations—regulating the development of cDC1 whereas modulating the functionality of pDCs without affecting development. We have reported here that Irf8R294C mutation also caused defect in production of ISGs as well as defective upregulation of costimulatory molecules in pDCs in response to NDV infection (or CpG stimulation). Through in vivo studies, we demonstrated that abrogation of type I IFN production was concomitant with reduced upregulation of costimulatory molecules in pDCs and increased NDV burden in IRF8R294C mice in comparison with wild type, indicating inefficient viral clearance. Further, we have also shown that Irf8R294C mutation abolished the activation of type I IFN promoter by IRF8, justifying the low level of type I IFN production. Taken together, our study signifies that the single point mutation in Irf8, Irf8R294C severely compromised type I IFN-mediated immune response by murine pDCs, thereby causing impairment in antiviral immunity.

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