| 1. |
- Aquila, Andrew, et al.
(författare)
-
Time-resolved protein nanocrystallography using an X-ray free-electron laser
- 2012
-
Ingår i: Optics Express. - 1094-4087. ; 20:3, s. 2706-2716
-
Tidskriftsartikel (refereegranskat)abstract
- We demonstrate the use of an X-ray free electron laser synchronized with an optical pump laser to obtain X-ray diffraction snapshots from the photoactivated states of large membrane protein complexes in the form of nanocrystals flowing in a liquid jet. Light-induced changes of Photosystem I-Ferredoxin co-crystals were observed at time delays of 5 to 10 µs after excitation. The result correlates with the microsecond kinetics of electron transfer from Photosystem I to ferredoxin. The undocking process that follows the electron transfer leads to large rearrangements in the crystals that will terminally lead to the disintegration of the crystals. We describe the experimental setup and obtain the first time-resolved femtosecond serial X-ray crystallography results from an irreversible photo-chemical reaction at the Linac Coherent Light Source. This technique opens the door to time-resolved structural studies of reaction dynamics in biological systems.
|
|
| 2. |
- Johansson, Linda C, 1983, et al.
(författare)
-
Lipidic phase membrane protein serial femtosecond crystallography.
- 2012
-
Ingår i: Nature methods. - : Springer Science and Business Media LLC. - 1548-7105 .- 1548-7091. ; 9:3, s. 263-265
-
Tidskriftsartikel (refereegranskat)abstract
- X-ray free electron laser (X-FEL)-based serial femtosecond crystallography is an emerging method with potential to rapidly advance the challenging field of membrane protein structural biology. Here we recorded interpretable diffraction data from micrometer-sized lipidic sponge phase crystals of the Blastochloris viridis photosynthetic reaction center delivered into an X-FEL beam using a sponge phase micro-jet.
|
|
| 3. |
- Johansson, Linda C, 1983, et al.
(författare)
-
Structure of a photosynthetic reaction centre determined by serial femtosecond crystallography.
- 2013
-
Ingår i: Nature communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 4
-
Tidskriftsartikel (refereegranskat)abstract
- Serial femtosecond crystallography is an X-ray free-electron-laser-based method with considerable potential to have an impact on challenging problems in structural biology. Here we present X-ray diffraction data recorded from microcrystals of the Blastochloris viridis photosynthetic reaction centre to 2.8Å resolution and determine its serial femtosecond crystallography structure to 3.5Å resolution. Although every microcrystal is exposed to a dose of 33MGy, no signs of X-ray-induced radiation damage are visible in this integral membrane protein structure.
|
|
| 4. |
- Arnlund, David, et al.
(författare)
-
Visualizing a protein quake with time-resolved X-ray scattering at a free-electron laser
- 2014
-
Ingår i: Nature Methods. - : Springer Science and Business Media LLC. - 1548-7091 .- 1548-7105. ; 11:9, s. 923-926
-
Tidskriftsartikel (refereegranskat)abstract
- We describe a method to measure ultrafast protein structural changes using time-resolved wide-angle X-ray scattering at an X-ray free-electron laser. We demonstrated this approach using multiphoton excitation of the Blastochloris viridis photosynthetic reaction center, observing an ultrafast global conformational change that arises within picoseconds and precedes the propagation of heat through the protein. This provides direct structural evidence for a 'protein quake': the hypothesis that proteins rapidly dissipate energy through quake-like structural motions.
|
|
| 5. |
- Barty, A., et al.
(författare)
-
Self-terminating diffraction gates femtosecond X-ray nanocrystallography measurements
- 2012
-
Ingår i: Nature Photonics. - 1749-4885 .- 1749-4893. ; 6:1, s. 35-40
-
Tidskriftsartikel (refereegranskat)abstract
- X-ray free-electron lasers have enabled new approaches to the structural determination of protein crystals that are too small or radiation-sensitive for conventional analysis1. For sufficiently short pulses, diffraction is collected before significant changes occur to the sample, and it has been predicted that pulses as short as 10 fs may be required to acquire atomic-resolution structural information1, 2, 3, 4. Here, we describe a mechanism unique to ultrafast, ultra-intense X-ray experiments that allows structural information to be collected from crystalline samples using high radiation doses without the requirement for the pulse to terminate before the onset of sample damage. Instead, the diffracted X-rays are gated by a rapid loss of crystalline periodicity, producing apparent pulse lengths significantly shorter than the duration of the incident pulse. The shortest apparent pulse lengths occur at the highest resolution, and our measurements indicate that current X-ray free-electron laser technology5 should enable structural determination from submicrometre protein crystals with atomic resolution.
|
|
| 6. |
- Bertini, Ivano, et al.
(författare)
-
Search for satellites near (21) Lutetia using OSIRIS/Rosetta images
- 2012
-
Ingår i: Planetary and Space Science. - : Elsevier BV. - 0032-0633 .- 1873-5088. ; 66:1, s. 64-70
-
Tidskriftsartikel (refereegranskat)abstract
- On 2010 July 10 the ESA Rosetta mission flew by the large asteroid (21) Lutetia. One of the scientific goals of the onboard OSIRIS instrument was the search for satellites of the asteroid, with more than 20 images specifically dedicated to this topic. An observational campaign was devised with a selection of filters and exposure times tailored to maximize the possibility of detecting small companions and determining their bound orbits. Data were analyzed with suitable methods to remove cosmic ray hits and known background objects, in order to search for persistent detections of potential interesting flux sources. We found no unambiguous detections of a satellite larger than similar to 160 m inside the entire sphere of gravitational influence. Our search confirmed the absence of bound companions larger than similar to 30 m inside 20 primary radii. These limits are a factor of similar to 30 smaller than the values reported so far from large ground-based telescopes using adaptive optics and from the Hubble Space Telescope.
|
|
| 7. |
- Björgvinsson, Erling, et al.
(författare)
-
Prototyping Futures
- 2012
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Prototyping Futures gives you a glimpse of what collaborating with academia might look like. Medea and its co-partners share their stories about activities happening at the research centre – projects, methods, tools, and approaches – what challenges lie ahead, and how these can be tackled. Examples of highlighted topics include: What is a living lab and how does it work? What are the visions behind the Connectivity Lab at Medea? And, how can prototyping-methods be used when sketching scenarios for sustainable futures? Other topics are: What is the role of the body when designing technology? What is collaborative media and how can this concept help us understand contemporary media practices? Prototyping Futures also discusses the open-hardware platform Arduino, and the concepts of open data and the Internet of Things, raising questions on how digital media and connected devices can contribute to more sustainable lifestyles, and a better world.
|
|
| 8. |
- Davidsson, Josef, et al.
(författare)
-
Relapsed childhood high hyperdiploid acute lymphoblastic leukemia : presence of preleukemic ancestral clones and the secondary nature of microdeletions and RTK-RAS mutations.
- 2010
-
Ingår i: Leukemia. - : Springer Science and Business Media LLC. - 0887-6924 .- 1476-5551. ; 24:5, s. 924-31
-
Tidskriftsartikel (refereegranskat)abstract
- Although childhood high hyperdiploid acute lymphoblastic leukemia is associated with a favorable outcome, 20% of patients still relapse. It is important to identify these patients already at diagnosis to ensure proper risk stratification. We have investigated 11 paired diagnostic and relapse samples with single nucleotide polymorphism array and mutation analyses of FLT3, KRAS, NRAS and PTPN11 in order to identify changes associated with relapse and to ascertain the genetic evolution patterns. Structural changes, mainly cryptic hemizygous deletions, were significantly more common at relapse (P<0.05). No single aberration was linked to relapse, but four deletions, involving IKZF1, PAX5, CDKN2A/B or AK3, were recurrent. On the basis of the genetic relationship between the paired samples, three groups were delineated: (1) identical genetic changes at diagnosis and relapse (2 of 11 cases), (2) clonal evolution with all changes at diagnosis being present at relapse (2 of 11) and (3) clonal evolution with some changes conserved, lost or gained (7 of 11), suggesting the presence of a preleukemic clone. This ancestral clone was characterized by numerical changes only, with structural changes and RTK-RAS mutations being secondary to the high hyperdiploid pattern.
|
|
| 9. |
- Hautmann, Richard E., et al.
(författare)
-
ICUD-EAU International Consultation on Bladder Cancer 2012: Urinary Diversion
- 2013
-
Ingår i: European Urology. - : Elsevier BV. - 1873-7560 .- 0302-2838. ; 63:1, s. 67-80
-
Forskningsöversikt (refereegranskat)abstract
- Context: A summary of the 2nd International Consultation on Bladder Cancer recommendations on the reconstructive options after radical cystectomy (RC), their outcomes, and their complications. Objective: To review the literature regarding indications, surgical details, postoperative care, complications, functional outcomes, as well as quality-of-life measures of patients with different forms of urinary diversion (UD). Evidence acquisition: An English-language literature review of data published between 1970 and 2012 on patients with UD following RC for bladder cancer was undertaken. No randomized controlled studies comparing conduit diversion with neobladder or continent cutaneous diversion have been performed. Consequently, almost all studies used in this report are of level 3 evidence. Therefore, the recommendations given here are grade C only, meaning expert opinion delivered without a formal analysis. Evidence synthesis: Indications and patient selection criteria have significantly changed over the past 2 decades. Renal function impairment is primarily caused by obstruction. Complications such as stone formation, urine outflow, and obstruction at any level must be recognized early and treated. In patients with orthotopic bladder substitution, daytime and nocturnal continence is achieved in 85-90% and 60-80%, respectively. Continence is inferior in elderly patients with orthotopic reconstruction. Urinary retention remains significant in female patients, ranging from 7% to 50%. Conclusions: RC and subsequent UD have been assessed as the most difficult surgical procedure in urology. Significant disparity on how the surgical complications were reported makes it impossible to compare postoperative morbidity results. Complications rates overall following RC and UD are significant, and when strict reporting criteria are incorporated, they are much higher than previously published. Fortunately, most complications are minor (Clavien grade 1 or 2). Complications can occur up to 20 yr after surgery, emphasizing the need for lifelong monitoring. Evidence suggests an association between surgical volume and outcome in RC; the challenge of optimum care for elderly patients with comorbidities is best mastered at high-volume hospitals by high-volume surgeons. Preoperative patient information, patient selection, surgical techniques, and careful postoperative follow-up are the cornerstones to achieve good long-term results. (C) 2012 European Association of Urology. Published by Elsevier B. V. All rights reserved.
|
|
| 10. |
- Koopmann, Rudolf, et al.
(författare)
-
In vivo protein crystallization opens new routes in structural biology
- 2012
-
Ingår i: Nature Methods. - : Springer Science and Business Media LLC. - 1548-7091 .- 1548-7105. ; 9:3, s. 259-262
-
Tidskriftsartikel (refereegranskat)abstract
- Protein crystallization in cells has been observed several times in nature. However, owing to their small size these crystals have not yet been used for X-ray crystallographic analysis. We prepared nano-sized in vivo–grown crystals of Trypanosoma brucei enzymes and applied the emerging method of free-electron laser-based serial femtosecond crystallography to record interpretable diffraction data. This combined approach will open new opportunities in structural systems biology.
|
|
