scholarly journals Co-crystal structure of the Fusobacterium ulcerans ZTP riboswitch using an X-ray free-electron laser

Author(s):  
Christopher Jones ◽  
Brandon Tran ◽  
Chelsie Conrad ◽  
Jason Stagno ◽  
Robert Trachman ◽  
...  

Riboswitches are conformationally dynamic RNAs that regulate gene expression by binding specific small molecules. ZTP riboswitches bind the purine-biosynthetic intermediate 5-aminoimidazole-4-carboxamide riboside 5′-monophosphate (ZMP) and its triphosphorylated form (ZTP). Ligand binding to this riboswitch ultimately upregulates genes involved in folate and purine metabolism. Using an X-ray free-electron laser (XFEL), the room-temperature structure of the Fusobacterium ulcerans ZTP riboswitch bound to ZMP has now been determined at 4.1 Å resolution. This model, which was refined against a data set from ∼750 diffraction images (each from a single crystal), was found to be consistent with that previously obtained from data collected at 100 K using conventional synchrotron X-radiation. These experiments demonstrate the feasibility of time-resolved XFEL experiments to understand how the ZTP riboswitch accommodates cognate ligand binding.

Author(s):  
Marius Schmidt ◽  
Suraj Pandey ◽  
Adrian Mancuso ◽  
Richard Bean

Abstract This protocol introduces step by step into the collection of time resolved crystallographic data and their analysis at the European Free Electron Laser.


2014 ◽  
Vol 369 (1647) ◽  
pp. 20130337 ◽  
Author(s):  
Uwe Weierstall

X-ray free-electron lasers overcome the problem of radiation damage in protein crystallography and allow structure determination from micro- and nanocrystals at room temperature. To ensure that consecutive X-ray pulses do not probe previously exposed crystals, the sample needs to be replaced with the X-ray repetition rate, which ranges from 120 Hz at warm linac-based free-electron lasers to 1 MHz at superconducting linacs. Liquid injectors are therefore an essential part of a serial femtosecond crystallography experiment at an X-ray free-electron laser. Here, we compare different techniques of injecting microcrystals in solution into the pulsed X-ray beam in vacuum. Sample waste due to mismatch of the liquid flow rate to the X-ray repetition rate can be addressed through various techniques.


2016 ◽  
Vol 24 (11) ◽  
pp. 11768 ◽  
Author(s):  
Nora Berrah ◽  
Li Fang ◽  
Brendan F Murphy ◽  
Edwin Kukk ◽  
Timur Y. Osipov ◽  
...  

2009 ◽  
Vol 80 (2) ◽  
Author(s):  
R. Mitzner ◽  
A. A. Sorokin ◽  
B. Siemer ◽  
S. Roling ◽  
M. Rutkowski ◽  
...  

Author(s):  
Robert J. Trachman ◽  
Jason R. Stagno ◽  
Chelsie Conrad ◽  
Christopher P. Jones ◽  
Pontus Fischer ◽  
...  

Turn-on aptamers are in vitro-selected RNAs that bind to conditionally fluorescent small molecules and enhance their fluorescence. Upon binding TO1-biotin, the iMango-III aptamer achieves the largest fluorescence enhancement reported for turn-on aptamers (over 5000-fold). This aptamer was generated by structure-guided engineering and functional reselection of the parental aptamer Mango-III. Structures of both Mango-III and iMango-III have previously been determined by conventional cryocrystallography using synchrotron X-radiation. Using an X-ray free-electron laser (XFEL), the room-temperature iMango-III–TO1-biotin co-crystal structure has now been determined at 3.0 Å resolution. This structural model, which was refined against a data set of ∼1300 diffraction images (each from a single crystal), is largely consistent with the structures determined from single-crystal data sets collected at 100 K. This constitutes a technical benchmark on the way to XFEL pump–probe experiments on fluorescent RNA–small molecule complexes.


Metrologia ◽  
2016 ◽  
Vol 53 (1) ◽  
pp. 98-102 ◽  
Author(s):  
T Tanaka ◽  
M Kato ◽  
N Saito ◽  
K Tono ◽  
M Yabashi ◽  
...  

Author(s):  
Wenting Wu ◽  
Przemyslaw Nogly ◽  
Jan Rheinberger ◽  
Leonhard M. Kick ◽  
Cornelius Gati ◽  
...  

Rhodopsin is a membrane protein from the G protein-coupled receptor family. Together with its ligand retinal, it forms the visual pigment responsible for night vision. In order to perform ultrafast dynamics studies, a time-resolved serial femtosecond crystallography method is required owing to the nonreversible activation of rhodopsin. In such an approach, microcrystals in suspension are delivered into the X-ray pulses of an X-ray free-electron laser (XFEL) after a precise photoactivation delay. Here, a millilitre batch production of high-density microcrystals was developed by four methodical conversion steps starting from known vapour-diffusion crystallization protocols: (i) screening the low-salt crystallization conditions preferred for serial crystallography by vapour diffusion, (ii) optimization of batch crystallization, (iii) testing the crystal size and quality using second-harmonic generation (SHG) imaging and X-ray powder diffraction and (iv) production of millilitres of rhodopsin crystal suspension in batches for serial crystallography tests; these crystals diffracted at an XFEL at the Linac Coherent Light Source using a liquid-jet setup.


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