Variation in the vulnerability of mice expressing human superoxide dismutase 1 to prion-like seeding: a study of the influence of primary amino acid sequence.

Misfolded forms of superoxide dismutase 1 (SOD1) with mutations associated with familial amyotrophic lateral sclerosis (fALS) exhibit prion characteristics, including the ability to act as seeds to accelerate motor neuron disease in mouse models. A key feature of infectious prion seeding is that the efficiency of transmission is governed by the primary sequence of prion protein (PrP). Isologous seeding, where the sequence of the PrP in the seed matches that of the host, is generally much more efficient than when there is a sequence mis-match.

A pH Switch Controls Zinc Binding in Tomato Copper-Zinc Superoxide Dismutase.

Copper-zinc superoxide dismutase (SOD1) is a major antioxidant metalloenzyme that protects cells from oxidative damage by superoxide anions (O). Structural, biophysical, and other characteristics have in the past been compiled for mammalian SOD1s and for the highly homologous fungal and bovine SOD1s. Here, we characterize the biophysical properties of a plant SOD1 from tomato chloroplasts and present several of its crystal structures.

Tryptophan residue 32 in human Cu-Zn superoxide dismutase modulates prion-like propagation and strain selection.

Mutations in Cu/Zn superoxide dismutase 1 (SOD1) associated with familial amyotrophic lateral sclerosis cause the protein to aggregate via a prion-like process in which soluble molecules are recruited to aggregates by conformational templating. These misfolded SOD1 proteins can propagate aggregation-inducing conformations across cellular membranes. Prior studies demonstrated that mutation of a Trp (W) residue at position 32 to Ser (S) suppresses the propagation of misfolded conformations between cells, whereas other studies have shown that mutation of Trp 32 to Phe (F), or Cys 111 to Ser, can act in cis to attenuate aggregation of mutant SOD1.

Nanoparticle Assisted Remodeling of Proteotoxic SOD1 Mutants Alters the Biointerface of the Functional Interaction of Microtubules and Kinesin Motors.

Transport deficits with motor neuron degeneration have been implicated in amyotrophic lateral sclerosis (ALS). We report a biomimetic system composed of microtubules/kinesin motor that mimics the dysregulated motor dynamics of ALS. Pathogenic ALS mutants A4V SOD1 completely shut off motility.

Localized Induction of Wild-Type and Mutant Alpha-Synuclein Aggregation Reveals Propagation along Neuroanatomical Tracts.

Misfolded alpha-synuclein (αS) may exhibit a number of characteristics similar to those of the prion protein, including the apparent ability to spread along neuroanatomical connections. The demonstration for this mechanism of spread is largely based on the intracerebral injections of preaggregated αS seeds in mice, in which it cannot be excluded that diffuse, surgical perturbations and hematogenous spread also contribute to the propagation of pathology. For this reason, we have utilized the sciatic nerve as a route of injection to force the inoculum into the lumbar spinal cord and induce a localized site for the onset of αS inclusion pathology.

Distinct conformers of transmissible misfolded SOD1 distinguish human SOD1-FALS from other forms of familial and sporadic ALS.

Evidence of misfolded wild-type superoxide dismutase 1 (SOD1) has been detected in spinal cords of sporadic ALS (sALS) patients, suggesting an etiological relationship to SOD1-associated familial ALS (fALS). Given that there are currently a number of promising therapies under development that target SOD1, it is of critical importance to better understand the role of misfolded SOD1 in sALS. We previously demonstrated the permissiveness of the G85R-SOD1:YFP mouse model for MND induction following injection with tissue homogenates from paralyzed transgenic mice expressing SOD1 mutations.

The Phylogeny and Active Site Design of Eukaryotic Copper-only Superoxide Dismutases.

In eukaryotes the bimetallic Cu/Zn superoxide dismutase (SOD) enzymes play important roles in the biology of reactive oxygen species by disproportionating superoxide anion. Recently, we reported that the fungal pathogen Candida albicans expresses a novel copper-only SOD, known as SOD5, that lacks the zinc cofactor and electrostatic loop (ESL) domain of Cu/Zn-SODs for substrate guidance. Despite these abnormalities, C.

Candida albicans SOD5 represents the prototype of an unprecedented class of Cu-only superoxide dismutases required for pathogen defense.

The human fungal pathogens Candida albicans and Histoplasma capsulatum have been reported to protect against the oxidative burst of host innate immune cells using a family of extracellular proteins with similarity to Cu/Zn superoxide dismutase 1 (SOD1). We report here that these molecules are widespread throughout fungi and deviate from canonical SOD1 at the primary, tertiary, and quaternary levels. The structure of C.

Aggregation-triggering segments of SOD1 fibril formation support a common pathway for familial and sporadic ALS.

ALS is a terminal disease of motor neurons that is characterized by accumulation of proteinaceous deposits in affected cells. Pathological deposition of mutated Cu/Zn superoxide dismutase (SOD1) accounts for ∼20% of the familial ALS (fALS) cases. However, understanding the molecular link between mutation and disease has been difficult, given that more than 140 different SOD1 mutants have been observed in fALS patients.

Structure of the Chlamydia trachomatis immunodominant antigen Pgp3.

Chlamydia trachomatis infection is the most common sexually transmitted bacterial disease. Left untreated, it can lead to ectopic pregnancy, pelvic inflammatory disease, and infertility. Here we present the structure of the secreted C.

Construction and analyses of tetrameric forms of yeast NAD+-specific isocitrate dehydrogenase.

Yeast NAD(+)-specific isocitrate dehydrogenase (IDH) is an octameric enzyme composed of four heterodimers of regulatory IDH1 and catalytic IDH2 subunits. The crystal structure suggested that the interactions between tetramers in the octamer are restricted to defined regions in IDH1 subunits from each tetramer. Using truncation and mutagenesis, we constructed three tetrameric forms of IDH.

Characterization of Pgp3, a Chlamydia trachomatis plasmid-encoded immunodominant antigen.

Human antibody recognition of Chlamydia trachomatis plasmid-encoded Pgp3 protein is dependent on the native conformation of Pgp3. The structural basis for the conformation dependence and the function of Pgp3 remain unknown. Here, we report that Pgp3 trimerization is required for the recognition of Pgp3 by human antibodies.

Structural and biophysical properties of metal-free pathogenic SOD1 mutants A4V and G93A.

Amyotrophic lateral sclerosis (ALS) is a fatal, progressive neurodegenerative disease characterized by the destruction of motor neurons in the spinal cord and brain. A subset of ALS cases are linked to dominant mutations in copper-zinc superoxide dismutase (SOD1). The pathogenic SOD1 variants A4V and G93A have been the foci of multiple studies aimed at understanding the molecular basis for SOD1-linked ALS.