| 1. |
- Woitowich, N. C., et al.
(författare)
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Structural basis for light control of cell development revealed by crystal structures of a myxobacterial phytochrome
- 2018
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Ingår i: Iucrj. - : International Union of Crystallography (IUCr). - 2052-2525. ; 5:Part 5, s. 619-634
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Tidskriftsartikel (refereegranskat)abstract
- Phytochromes are red-light photoreceptors that were first characterized in plants, with homologs in photosynthetic and non-photosynthetic bacteria known as bacteriophytochromes (BphPs). Upon absorption of light, BphPs interconvert between two states denoted Pr and Pfr with distinct absorption spectra in the red and far-red. They have recently been engineered as enzymatic photoswitches for fluorescent-marker applications in non-invasive tissue imaging of mammals. This article presents cryo- and room-temperature crystal structures of the unusual phytochrome from the non-photosynthetic myxobacterium Stigmatella aurantiaca (SaBphP1) and reveals its role in the fruitingbody formation of this photomorphogenic bacterium. SaBphP1 lacks a conserved histidine (His) in the chromophore-binding domain that stabilizes the Pr state in the classical BphPs. Instead it contains a threonine (Thr), a feature that is restricted to several myxobacterial phytochromes and is not evolutionarily understood. SaBphP1 structures of the chromophore binding domain (CBD) and the complete photosensory core module (PCM) in wild-type and Thr-to-His mutant forms reveal details of the molecular mechanism of the Pr/Pfr transition associated with the physiological response of this myxobacterium to red light. Specifically, key structural differences in the CBD and PCM between the wild-type and the Thr-to-His mutant involve essential chromophore contacts with proximal amino acids, and point to how the photosignal is transduced through the rest of the protein, impacting the essential enzymatic activity in the photomorphogenic response of this myxobacterium.
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| 2. |
- Edlund, Petra, et al.
(författare)
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The room temperature crystal structure of a bacterial phytochrome determined by serial femtosecond crystallography
- 2016
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Phytochromes are a family of photoreceptors that control light responses of plants, fungi and bacteria. A sequence of structural changes, which is not yet fully understood, leads to activation of an output domain. Time-resolved serial femtosecond crystallography (SFX) can potentially shine light on these conformational changes. Here we report the room temperature crystal structure of the chromophore-binding domains of the Deinococcus radiodurans phytochrome at 2.1 angstrom resolution. The structure was obtained by serial femtosecond X-ray crystallography from microcrystals at an X-ray free electron laser. We find overall good agreement compared to a crystal structure at 1.35 angstrom resolution derived from conventional crystallography at cryogenic temperatures, which we also report here. The thioether linkage between chromophore and protein is subject to positional ambiguity at the synchrotron, but is fully resolved with SFX. The study paves the way for time-resolved structural investigations of the phytochrome photocycle with time-resolved SFX.
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| 3. |
- Berg, S., et al.
(författare)
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Serotypes of Streptococcus pneumoniae isolated from blood and cerebrospinal fluid related to vaccine serotypes and to clinical characteristics
- 2006
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Ingår i: Scand J Infect Dis. - : Informa UK Limited. - 0036-5548. ; 38:6-7, s. 427-32
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Tidskriftsartikel (refereegranskat)abstract
- Pneumococci isolated from blood and cerebrospinal fluid from 1998 to 2001 in 2 counties in south-west Sweden were serotyped with the capsular reaction test. Of the 836 strains, 353 (42%), 598 (72%) and 789 (94%) belonged to serotypes included in the 7- and 11-valent pneumococcal conjugate vaccines and in the 23-valent polysaccharide vaccine, respectively. The most common serotype was type 1 (119 isolates) followed in descending frequency by serotypes 7F, 9V, 14, 4 and 12F (90-49 isolates per serotype). The coverage rates of the 7- and 11-valent conjugate vaccines among 58 strains isolated from children and adolescents 0-19 y of age were 46% and 93%, respectively. A comparison of clinical characteristics of infections caused by different serotypes showed that types 1 and 7F were less commonly associated with severe underlying diseases, that patients infected with these serotypes were younger than the average and, thus, had a lower case-fatality rate.
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| 4. |
- Carrillo, M., et al.
(författare)
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High-resolution crystal structures of transient intermediates in the phytochrome photocycle
- 2021
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Ingår i: Structure. - : Elsevier BV. - 0969-2126. ; 29:7
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Tidskriftsartikel (refereegranskat)abstract
- Phytochromes are red/far-red light photoreceptors in bacteria to plants, which elicit a variety of important physiological responses. They display a reversible photocycle between the resting Pr state and the light-activated Pfr state. Light signals are transduced as structural change through the entire protein to modulate its activity. It is unknown how the Pr-to-Pfr interconversion occurs, as the structure of intermediates remains notoriously elusive. Here, we present short-lived crystal structures of the photosensory core modules of the bacteriophytochrome from myxobacterium Stigmatella aurantiaca captured by an X-ray free electron laser 5 ns and 33 ms after light illumination of the Pr state. We observe large structural displacements of the covalently bound bilin chromophore, which trigger a bifurcated signaling pathway that extends through the entire protein. The snapshots show with atomic precision how the signal progresses from the chromophore, explaining how plants, bacteria, and fungi sense red light.
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| 5. |
- Cellini, Andrea, 1991, et al.
(författare)
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The three-dimensional structure of Drosophila melanogaster (6-4) photolyase at room temperature
- 2021
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Ingår i: Acta Crystallographica Section D-Structural Biology. - : International Union of Crystallography (IUCr). - 2059-7983. ; 77, s. 1001-1009
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Tidskriftsartikel (refereegranskat)abstract
- (6-4) photolyases are flavoproteins that belong to the photolyase/cryptochrome family. Their function is to repair DNA lesions using visible light. Here, crystal structures of Drosophila melanogaster (6-4) photolyase [Dm(6-4)photolyase] at room and cryogenic temperatures are reported. The room-temperature structure was solved to 2.27 angstrom resolution and was obtained by serial femtosecond crystallography (SFX) using an X-ray free-electron laser. The crystallization and preparation conditions are also reported. The cryogenic structure was solved to 1.79 angstrom resolution using conventional X-ray crystallography. The structures agree with each other, indicating that the structural information obtained from crystallography at cryogenic temperature also applies at room temperature. Furthermore, UV-Vis absorption spectroscopy confirms that Dm(6-4)photolyase is photoactive in the crystals, giving a green light to time-resolved SFX studies on the protein, which can reveal the structural mechanism of the photoactivated protein in DNA repair.
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| 6. |
- Claesson, Elin, 1989, et al.
(författare)
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The primary structural photoresponse of phytochrome proteins captured by a femtosecond X-ray laser
- 2020
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Ingår i: eLife. - 2050-084X. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Phytochrome proteins control the growth, reproduction, and photosynthesis of plants, fungi, and bacteria. Light is detected by a bilin cofactor, but it remains elusive how this leads to activation of the protein through structural changes. We present serial femtosecond X-ray crystallographic data of the chromophore-binding domains of a bacterial phytochrome at delay times of 1 ps and 10 ps after photoexcitation. The data reveal a twist of the D-ring, which leads to partial detachment of the chromophore from the protein. Unexpectedly, the conserved so-called pyrrole water is photodissociated from the chromophore, concomitant with movement of the A-ring and a key signaling aspartate. The changes are wired together by ultrafast backbone and water movements around the chromophore, channeling them into signal transduction towards the output domains. We suggest that the observed collective changes are important for the phytochrome photoresponse, explaining the earliest steps of how plants, fungi and bacteria sense red light.
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| 7. |
- Hwang, K. -H, et al.
(författare)
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Growth of self-template 3D gold nanoparticles on boron nanowire arrays for surface plasmon resonance biosensor application
- 2018
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Ingår i: Encyclopedia of Interfacial Chemistry: Surface Science and Electrochemistry. - : Elsevier. - 9780128098943 - 9780128097397 ; , s. 460-464
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Enabling detection of target molecules at low concentration is a key feature in localized surface plasmon resonance (LSPR) biosensors, which utilizes the remarkable optical properties of metal nanoparticles such as gold (Au) and silver (Ag) induced by the excitation of LSPR. However, the clear interrelationship between three-dimensional (3D) metal nanoparticle topography and localization of SPR is not fully understood. For the studies, we here propose and demonstrate an approach for fabricating new type of self-template 3D Au nanostructures by using boron nanowire arrays (BNWs) as a building block grown by oxide-assisted vapor-liquid-solid (VLS) mode at relatively low temperatures. This is the first report on formation of 3D Au pores and clusters induced by boron oxide (B2O3) below 500°C.
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| 8. |
- Sanchez, J. C., et al.
(författare)
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High-resolution crystal structures of amyxobacterial phytochrome at cryo and roomtemperatures
- 2019
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Ingår i: Structural Dynamics-Us. - : AIP Publishing. - 2329-7778. ; 6:5
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Tidskriftsartikel (refereegranskat)abstract
- Phytochromes (PHYs) are photoreceptor proteins first discovered in plants, where they control a variety of photomorphogenesis events. PHYs as photochromic proteins can reversibly switch between two distinct states: a red light (Pr) and a far-red light (Pfr) absorbing form. The discovery of Bacteriophytochromes (BphPs) in nonphotosynthetic bacteria has opened new frontiers in our understanding of the mechanisms by which these natural photoswitches can control single cell development, although the role of BphPs in vivo remains largely unknown. BphPs are dimeric proteins that consist of a photosensory core module (PCM) and an enzymatic domain, often a histidine kinase. The PCM is composed of three domains (PAS, GAF, and PHY). It holds a covalently bound open-chain tetrapyrrole (biliverdin, BV) chromophore. Upon absorption of light, the double bond between BV rings C and D isomerizes and reversibly switches the protein between Pr and Pfr states. We report crystal structures of the wild-type and mutant (His275Thr) forms of the canonical BphP from the nonphotosynthetic myxobacterium Stigmatella aurantiaca (SaBphP2) in the Pr state. Structures were determined at 1.65A degrees and 2.2A degrees (respectively), the highest resolution of any PCM construct to date. We also report the room temperature wild-type structure of the same protein determined at 2.1A degrees at the SPring-8 Angstrom Compact free electron LAser (SACLA), Japan. Our results not only highlight and confirm important amino acids near the chromophore that play a role in Pr-Pfr photoconversion but also describe the signal transduction into the PHY domain which moves across tens of angstroms after the light stimulus. (C) 2019 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
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| 9. |
- Öhlander, Björn, et al.
(författare)
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Delineation and character of the Archaean-Proterozoic boundary in northern Sweden
- 1993
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Ingår i: Precambrian Research. - 0301-9268 .- 1872-7433. ; 64:1-4, s. 67-84
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Tidskriftsartikel (refereegranskat)abstract
- Before the deposition of a Proterozoic cover and the repeated Proterozoic reworking of the older rocks, the presently exposed Archaean areas in northern Sweden formed part of a coherent craton. In the present study, we have used Sm---Nd isotopic analyses of Proterozoic granitoids and metavolcanics to delineate the Archaean palaeoboundary. In a regional context, the transition from strongly negative εNd(t) values in the northeast to positive values in the southwest is distinct, and approximately defines the border of the old craton. The Archaean palaeoboundary extends in a WNW direction, and is subparallel to the longitudinal axis of the Skellefte sulphide ore district but it is situated ≈ 100 km farther to the north. The ≈ 1.9 Ga old granitoids on the two sides of the palaeoboundary were all formed in compressional environments, but those situated to the north have higher contents of LILE and LREE at similar contents of Si. This indicates that they were generated in an area with thicker crust and supports the location of the Archaean-Proterozoic palaeoboundary. There is no simple correlation between the Archaean palaeoboundary, as defined by the isotopic results, and any of the major fracture systems as interpreted from regional geophysical measurements. Reflection seismic work indicates that juvenile volcanic-arc terrains to the south have been thrust onto the Archaean craton. Possible thrust faults have been identified from aeromagnetic measurements. Rifting of the Archaean craton created a passive margin ≈ 2.0 Ga ago. Spreading shifted to convergence with subduction beneath the Archaean continent ≈ 1.9 Ga ago. Subsequently, the resulting juvenile volcanic arc collided with the old continent, and the Archaean palaeoboundary as existing today was formed by a collision characterized by overthrusting. The boundary then was disturbed by later deformation predominantly along NNE-trending fracture systems.
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| 10. |
- Berg, S, et al.
(författare)
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Incidence and prognosis of meningitis due to Haemophilus influenzae, Streptococcus pneumoniae and Neisseria meningitidis in Sweden.
- 1996
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Ingår i: Scandinavian Journal of Infectious Diseases. - : Informa UK Limited. - 0036-5548 .- 1651-1980. ; 28:3, s. 247-52
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Tidskriftsartikel (refereegranskat)abstract
- The incidence, concomitant conditions and case fatality rate of Haemophilus influenzae (Hi) and pneumococcal meningitis and of invasive meningococcal infections were studied retrospectively in Sweden (population 8.4 million) for the years 1987-89, the period before vaccination against Hi type b started. A total of 1,019 cases with culture-verified infection were found. The incidence rates per 100,000 per year were 1.8 for Hi meningitis, 1.2 for pneumococcal meningitis and 1.0 for invasive meningococcal infections. The age-specific incidence was highest in the 3-23 months age group for the 3 bacterial species. Pneumococcal meningitis was common in individuals > or = 60 years and meningococcal infections in the age-group 10-24 years. A serious concomitant condition was known in 57% of all patients with pneumococcal meningitis while this was uncommon for the other organisms. The case fatality rate was 2% for Hi meningitis, 24% for pneumococcal meningitis and 10% for meningococcal infections. All 81 pneumococcal isolates which had been serotyped belonged to serotypes in the 23-valent pneumococcal vaccine. Of the meningococcal isolates, 65% belonged to serogroup B. In conclusion, the high incidence of Hib meningitis justifies general Hib vaccination. Development of a vaccine against N. meningitidis group B should have high priority. Furthermore, improved pneumococcal vaccines are needed for patients with predisposing conditions. The currently available pneumococcal polysaccharide vaccine seems to be underused.
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