| 1. |
- Berntsson, Ronnie P. -A., et al.
(författare)
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Structural insight into DNA binding and oligomerization of the multifunctional Cox protein of bacteriophage P2
- 2014
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Ingår i: Nucleic Acids Research. - : Oxford University Press (OUP). - 0305-1048 .- 1362-4962. ; 42:4, s. 2725-2735
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Tidskriftsartikel (refereegranskat)abstract
- The Cox protein from bacteriophage P2 is a small multifunctional DNA-binding protein. It is involved in site-specific recombination leading to P2 prophage excision and functions as a transcriptional repressor of the P2 Pc promoter. Furthermore, it transcriptionally activates the unrelated, defective prophage P4 that depends on phage P2 late gene products for lytic growth. In this article, we have investigated the structural determinants to understand how P2 Cox performs these different functions. We have solved the structure of P2 Cox to 2.4 angstrom resolution. Interestingly, P2 Cox crystallized in a continuous oligomeric spiral with its DNA-binding helix and wing positioned outwards. The extended C-terminal part of P2 Cox is largely responsible for the oligomerization in the structure. The spacing between the repeating DNA-binding elements along the helical P2 Cox filament is consistent with DNA binding along the filament. Functional analyses of alanine mutants in P2 Cox argue for the importance of key residues for protein function. We here present the first structure from the Cox protein family and, together with previous biochemical observations, propose that P2 Cox achieves its various functions by specific binding of DNA while wrapping the DNA around its helical oligomer.
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| 2. |
- Frantzen, Astri Tafjord, et al.
(författare)
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Frailty Status and Patient-Reported Outcomes in Octogenarians Following Transcatheter or Surgical Aortic Valve Replacement
- 2021
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Ingår i: Heart, Lung and Circulation. - : Elsevier. - 1443-9506 .- 1444-2892. ; 30:8, s. 1221-1231
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundFrailty status and patient-reported outcomes are especially pertinent in octogenarians following transcatheter aortic valve implantation (TAVI) and surgical aortic valve replacement (SAVR) to guide treatment decisions and promote patient-centred care.AimWe aimed to determine if frailty changed 6 months after aortic valve replacement (AVR) in octogenarians, and to describe changes in self-rated health according to frailty status in patients who underwent TAVI or SAVR.MethodIn a prospective cohort study, frailty and self-rated health were measured one day prior to and 6 months after AVR. Frailty status was measured with the Study of Osteoporotic Fracture index. Self-rated health was measured comprehensively with the disease-specific Minnesota Living with Heart Failure Questionnaire, the generic Medical Outcomes Study Short Form-12 questionnaire (SF-12), and two global questions from The World Health Organization Quality of Life Instrument Abbreviated.ResultsData were available for 143 consecutive patients (mean age 83 +/- 2.7 years, 57% women; 45% underwent TAVI). At baseline, 34% were robust, 27% prefrail, and 39% frail. Overall, there was no change in the distribution of frailty status 6 months after baseline (p=0.13). However, on an individual level 65 patients changed frailty status after AVR (40 patients improved and 25 declined). Improvement in frailty status was common in prefrail (33%; n=13) and frail patients (48%; n=27). Patients had improved self-rated health after AVR, with significant differences between frailty states both at baseline (SF-12 physical: 37.4 [robust], 33.1 [prefrail], 31.6 [frail], p=0.03); SF-12 mental: 51.9 [robust], 50.8 [prefrail], 44.5 [frail], p<0.001); and at the 6-month follow-up (SF-12 physical: 45.4 [robust], 38.3 [prefrail], 32.1 [frail], p<0.001); SF-12 mental: 54.9 [robust], 49.6 [prefrail], 46.8 [frail], p=0.002).ConclusionsAdvanced treatment performed in a high-risk population allowed people to improve their self-rated health. Although frailty is associated with poor self-rated health, frailty status does not equal negative outcomes. The frail patients were those who improved most in self-rated physical and mental health. They had the lowest baseline self-rated health scores and had therefore the most to gain.
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| 3. |
- Massad, Tariq, et al.
(författare)
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Crystal structure of the P2 C-repressor : a binder of nonpalindromic direct DNA repeats
- 2010
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Ingår i: Nucleic Acids Research. - : Oxford University Press (OUP). - 0305-1048 .- 1362-4962. ; 38:21, s. 7778-7790
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Tidskriftsartikel (refereegranskat)abstract
- As opposed to the vast majority of prokaryoticrepressors, the immunity repressor of temperateEscherichia coli phage P2 (C) recognizes nonpalindromicdirect repeats of DNA rather thaninverted repeats. We have determined the crystalstructure of P2 C at 1.8A ° . This constitutes the firststructure solved from the family of C proteins fromP2-like bacteriophages. The structure reveals thatthe P2 C protein forms a symmetric dimer orientedto bind the major groove of two consecutive turns ofthe DNA. Surprisingly, P2 C has great similarities tobinders of palindromic sequences. Nevertheless, thetwo identical DNA-binding helixes of the symmetricP2 C dimer have to bind different DNA sequences.Helix 3 is identified as the DNA-recognition motif inP2 C by alanine scanning and the importance for theindividual residues in DNA recognition is defined.A truncation mutant shows that the disorderedC-terminus is dispensable for repressor function.The short distance between the DNA-bindinghelices together with a possible interaction betweentwo P2 C dimers are proposed to be responsible forextensive bending of the DNA. The structure providesinsight into the mechanisms behind the mutants ofP2 C causing dimer disruption, temperature sensitivityand insensitivity to the P4 antirepressor.
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| 4. |
- Olsen, Siv J. S., et al.
(författare)
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Changes in self-reported health and quality of life in octogenarian patients one month after transcatheter aortic valve implantation
- 2017
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Ingår i: European Journal of Cardiovascular Nursing. - : Sage Publications. - 1474-5151 .- 1873-1953. ; 16:1, s. 79-87
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: In addition to favourable results regarding mortality and morbidity it is important to identify the impact transcatheter aortic valve implantation (TAVI) has on patients' quality of life.AIMS: The aims were: (i) to describe clinical characteristics, self-reported health and quality of life in octogenarians before TAVI intervention; (ii) to determine changes in self-reported health and quality of life one month after TAVI; and (iii) to establish the clinical importance of the findings.METHODS: A prospective cohort study was conducted on consecutively enrolled octogenarians with severe aortic stenosis undergoing TAVI (N = 65). Self-reported health and quality of life were recorded at baseline and one month later using two global questions from the World Health Organization Quality of Life Instrument Abbreviated (WHOQOL-BREF), the generic Short Form Health 12 and the disease-specific Minnesota Living with Heart Failure Questionnaire.RESULTS: One month after TAVI, WHOQOL-BREF showed that self-reported health improved moderately (p < 0.001), while quality of life improved slightly, but not statistically significantly (p = 0.06). There were changes in all Short Form Health 12 domains, except social functioning and role emotional. The estimated changes were 3.6 to 5.8 with large confidence intervals. The Physical Component Summary increased statistically significantly from baseline to 30 days (30.6-34.7; p = 0.02), but the Mental Component Summary did not (46.9-50.0; p = 0.13).CONCLUSION: Despite being an advanced treatment performed in a high risk population, TAVI in octogenarians improves short-term self-reported global health and generic physical health and quality of life. These patient-reported outcomes have importance, particularly in this age group.
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| 5. |
- Skaar, Karin, et al.
(författare)
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Crystal structure of the bacteriophage P2 integrase catalytic domain
- 2015
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Ingår i: FEBS Letters. - : Wiley. - 0014-5793 .- 1873-3468. ; 589:23, s. 3556-3563
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Tidskriftsartikel (refereegranskat)abstract
- Bacteriophage P2 is a temperate phage capable of integrating its DNA into the host genome by site-specific recombination upon lysogenization. Integration and excision of the phage genome requires P2 integrase, which performs recognition, cleavage and joining of DNA during these processes. This work presents the high-resolution crystal structure of the catalytic domain of P2 integrase, and analysis of several non-functional P2 integrase mutants. The DNA binding area is characterized by a large positively charged patch, harbouring key residues. The structure reveals potential for large dimer flexibility, likely essential for rearrangement of DNA strands upon integration and excision.
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