| 1. |
- Kanai, M, et al.
(författare)
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- 2023
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swepub:Mat__t
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| 2. |
- Niemi, MEK, et al.
(författare)
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- 2021
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swepub:Mat__t
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| 3. |
- Lennerstrand, Johan, et al.
(författare)
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Correlation between viral resistance to zidovudine and resistance at the reverse transcriptase level for a panel of human immunodeficiency virus type 1 mutants
- 2001
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Ingår i: Journal of Virology. - 0022-538X .- 1098-5514. ; 75:15, s. 7202-7205
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Tidskriftsartikel (refereegranskat)abstract
- Using a large panel of human immunodeficiency virus type 1 site-directed mutants, we have observed a higher correlation than has previously been demonstrated between zidovudine (AZT)-triphosphate resistance data at the reverse transcriptase (RT) level and corresponding viral AZT resistance. This enhanced-resistance effect at the RT level was seen with ATP and to a lesser extent with PP(i) when ATP was added at physiological concentrations. The ATP-dependent mechanism (analogous to pyrophosphorolysis) appears to be dominant in the mutants bearing the D67N and K70R or 69 insertion mutations, whereas the Q151M mutation seems independent of ATP for decreased binding to AZT-triphosphate.
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| 4. |
- Lloyd, B., et al.
(författare)
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Overview of physics results from MAST
- 2007
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Ingår i: Nuclear Fusion. - 0029-5515 .- 1741-4326. ; 47:10, s. S658-S667
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Tidskriftsartikel (refereegranskat)abstract
- Substantial advances have been made on the Mega AmpÚre Spherical Tokamak (MAST). The parameter range of the MAST confinement database has been extended and it now also includes pellet-fuelled discharges. Good pellet retention has been observed in H-mode discharges without triggering an ELM or an H/L transition during peripheral ablation of low speed pellets. Co-ordinated studies on MAST and DIII-D demonstrate a strong link between the aspect ratio and the beta scaling of H-mode energy confinement, consistent with that obtained when MAST data were merged with a subset of the ITPA database. Electron and ion ITBs are readily formed and their evolution has been investigated. Electron and ion thermal diffusivities have been reduced to values close to the ion neoclassical level. Error field correction coils have been used to determine the locked mode threshold scaling which is comparable to that in conventional aspect ratio tokamaks. The impact of plasma rotation on sawteeth has been investigated and the results have been well-modelled using the MISHKA-F code. Alfvén cascades have been observed in discharges with reversed magnetic shear. Measurements during off-axis NBCD and heating are consistent with classical fast ion modelling and indicate efficient heating and significant driven current. Central electron Bernstein wave heating has been observed via the O-X-B mode conversion process in special magnetically compressed plasmas. Plasmas with low pedestal collisionality have been established and further insight has been gained into the characteristics of filamentary structures at the plasma edge. Complex behaviour of the divertor power loading during plasma disruptions has been revealed by high resolution infra-red measurements.
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| 5. |
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| 6. |
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| 7. |
- Lennerstrand, Johan, et al.
(författare)
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Biochemical mechanism of human immunodeficiency virus type 1 reverse transcriptase resistance to stavudine
- 2001
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Ingår i: Antimicrobial Agents and Chemotherapy. - 0066-4804 .- 1098-6596. ; 45:7, s. 2144-2146
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Tidskriftsartikel (refereegranskat)abstract
- We have found a close correlation between viral stavudine (d4T) resistance and resistance to d4T-triphosphate at the human immunodeficiency virus type 1 reverse transcriptase (RT) level. RT from site-directed mutants with 69S-XX codon insertions and/or conventional zidovudine resistance mutations seems to be involved in an ATP-dependent resistance mechanism analogous to pyrophosphorolysis, whereas the mechanism for RT with the Q151M or V75T mutation appears to be independent of added ATP for reducing binding to d4T-triphosphate.
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| 8. |
- Rinaldo-Matthis, Agnes, 1971-
(författare)
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Crystal structures of human deoxyribonucleotidases
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Human 5’-deoxyribonucleotidases are ubiquitous enzymes that catalyze the dephosphorylation of deoxyribonucleoside monophosphates to their nucleoside form. They participate in the regulation of deoxyribonucleotide pools and protect DNA replication from inbalance of precursors. The observed specificity of the cytosolic 5’-deoxyribonucleotidase (cdN) and the mitochondrial 5’-deoxyribonucleotidase (mdN) is similar and both enzymes prefer the pyrimidine-based nucleotides such as dUMP and dTMP as substrates although cdN can also dephosphorylate dIMP and dGMP.The structures of the two isoforms of the human deoxyribonucleotidases have been determined using X-ray crystallography and allowed us to propose a catalytic mechanism for this family of enzymes and to map residues involved in substrate binding.The structures of cdN and mdN reveal dimeric proteins belonging to the HAD structural family, with a phosphoserine phosphatase (PSP) as the closest structural neighbour. The subunit is formed by two domains with the active site located in a crevice in between the domains. The active site contains a Mg2+ ion and a cluster of four aspartic residues. Asp41 is proposed to serve as the catalytic nucleophile and Asp43 as having a dual function in a general acid/base catalysis. Several structural complexes have been determined, with substrates, products, inhibitors and analogs of reaction intermediates. These substrate/product complexes reveal important residues for substrate specificity recognition. AlF4-/BeF3--compounds have been used to form structurecomplexes, which mimic formation of phosphoenzyme intermediates during catalysis. The study of the structural differences between the two enzymes, cdN and mdN, makes it possible to understand the differences in substrate recognition and inhibition pattern.
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| 9. |
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