| 1. |
- Pushparaj, Pradeepa, et al.
(författare)
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Immunoglobulin germline gene polymorphisms influence the function of SARS-CoV-2 neutralizing antibodies
- 2023
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Ingår i: Immunity. - : Elsevier BV. - 1074-7613 .- 1097-4180. ; 56:1, s. 7-206
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Tidskriftsartikel (refereegranskat)abstract
- The human immunoglobulin heavy-chain (IGH) locus is exceptionally polymorphic, with high levels of allelic and structural variation. Thus, germline IGH genotypes are personal, which may influence responses to infection and vaccination. For an improved understanding of inter-individual differences in antibody responses, we isolated SARS-CoV-2 spike-specific monoclonal antibodies from convalescent health care workers, focusing on the IGHV1-69 gene, which has the highest level of allelic variation of all IGHV genes. The IGHV1-69∗20-using CAB-I47 antibody and two similar antibodies isolated from an independent donor were critically dependent on allele usage. Neutralization was retained when reverting the V region to the germline IGHV1-69∗20 allele but lost when reverting to other IGHV1-69 alleles. Structural data confirmed that two germline-encoded polymorphisms, R50 and F55, in the IGHV1-69 gene were required for high-affinity receptor-binding domain interaction. These results demonstrate that polymorphisms in IGH genes can influence the function of SARS-CoV-2 neutralizing antibodies.
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| 2. |
- Furlanetto, Valentina, et al.
(författare)
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Structural and Functional Characterization of a Gene Cluster Responsible for Deglycosylation of C-glucosyl Flavonoids and Xanthonoids by Deinococcus aerius
- 2024
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Ingår i: Journal of Molecular Biology. - : Elsevier BV. - 0022-2836 .- 1089-8638. ; 436:9
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Tidskriftsartikel (refereegranskat)abstract
- Plant C-glycosylated aromatic polyketides are important for plant and animal health. These are specialized metabolites that perform functions both within the plant, and in interaction with soil or intestinal microbes. Despite the importance of these plant compounds, there is still limited knowledge of how they are metabolized. The Gram-positive aerobic soil bacterium Deinococcus aerius strain TR0125 and other Deinococcus species thrive in a wide range of harsh environments. In this work, we identified a C-glycoside deglycosylation gene cluster in the genome of D. aerius. The cluster includes three genes coding for a GMC-type oxidoreductase (DaCGO1) that oxidizes the glucosyl C3 position in aromatic C-glucosyl compounds, which in turn provides the substrate for the C-glycoside deglycosidase (DaCGD; composed of α+β subunits) that cleaves the glucosyl-aglycone C–C bond. Our results from size-exclusion chromatography, single particle cryo-electron microscopy and X-ray crystallography show that DaCGD is an α2β2 heterotetramer, which represents a novel oligomeric state among bacterial CGDs. Importantly, the high-resolution X-ray structure of DaCGD provides valuable insights into the activation of the catalytic hydroxide ion by Lys261. DaCGO1 is specific for the 6-C-glucosyl flavones isovitexin, isoorientin and the 2-C-glucosyl xanthonoid mangiferin, and the subsequent C–C-bond cleavage by DaCGD generated apigenin, luteolin and norathyriol, respectively. Of the substrates tested, isovitexin was the preferred substrate (DaCGO1, Km 0.047 mM, kcat 51 min−1; DaCGO1/DaCGD, Km 0.083 mM, kcat 0.42 min−1).
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| 3. |
- Hällberg, B. Martin, et al.
(författare)
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Crystallization and preliminary X-ray diffraction analysis of pyranose 2-oxidase from the white-rot fungus Trametes multicolor
- 2004
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Ingår i: Acta Crystallographica Section D. - : International Union of Crystallography (IUCr). - 0907-4449 .- 1399-0047. ; 60, s. 197-199
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Tidskriftsartikel (refereegranskat)abstract
- Pyranose 2-oxidase (P2Ox) is a 270 kDa homotetrameric flavoenzyme that catalyzes the oxidation of D-glucose to 2-keto-D-glucose. P2Ox participates in lignin degradation by white-rot fungi and a tentative role of the enzyme is the production of H2O2 for lignin peroxidases. Crystals of Trametes multicolor P2Ox were grown from monomethylether PEG 2000, sodium acetate, MgCl2 and Ta6Br12. They belong to space group P2(1), with unit-cell parameters a = 99.9, b = 101.7, c = 135.6 Angstrom, beta = 90.85degrees. X-ray diffraction data to 2.0 Angstrom resolution were collected using synchrotron radiation. Self-rotation function calculations suggest that the asymmetric unit contains one homotetramer with 222 point-group symmetry.
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| 4. |
- Hällberg, B Martin, et al.
(författare)
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Making proteins in the powerhouse
- 2014
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Ingår i: Cell Metabolism. - Stockholm : Karolinska Institutet, Dept of Cell and Molecular Biology. - 1550-4131 .- 1932-7420.
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Tidskriftsartikel (refereegranskat)abstract
- Understanding regulation of mitochondrial DNA (mtDNA) expression is of considerable interest as mitochondrial dysfunction is important in human pathology and ageing. Similar to the situation in bacteria, there is no compartmentalization between transcription and translation in mitochondria; hence, both processes are likely to have a direct molecular crosstalk. Accumulating evidence suggests that there are important mechanisms for regulation of mammalian mtDNA expression at the posttranscriptional level. Regulation of mRNA maturation, mRNA stability, translational coordination, ribosomal biogenesis and translation itself, all form the basis for controlling oxidative phosphorylation capacity. Consequently, a wide variety of inherited human mitochondrial diseases are caused by mutations of nuclear genes regulating various aspects of mitochondrial translation. Furthermore, mutations of mtDNA, associated with human disease and ageing, often affect tRNA genes critical for mitochondrial translation. Recent advances in molecular understanding of mitochondrial translation regulation will likely provide novel avenues for modulating mitochondrial function to treat human disease.
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| 5. |
- Hällberg, B Martin, et al.
(författare)
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TFAM forces mtDNA to make a U-turn
- 2011
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Ingår i: Nature Structural and Molecular Biology. - Stockholm : Karolinska Institutet, Dept of Cell and Molecular Biology. - 1545-9993 .- 1545-9985.
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Tidskriftsartikel (refereegranskat)abstract
- The mammalian mitochondrial transcription factor A (TFAM) is encoded in the nucleus and imported into mitochondria, where it functions as an activator of mtDNA transcription and packages mtDNA into DNA-protein aggregates called mitochondrial nucleoids. Two X-ray crystallography studies in this issue reveal that TFAM shapes mtDNA into a sharp U-turn, thereby providing a molecular mechanism for its dual roles in the expression and maintenance of mtDNA.
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