ORCID Profile
0000-0002-1919-8649
Current Organisation
Institut de Biologie Structurale
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Publisher: Elsevier BV
Date: 02-2013
DOI: 10.1016/J.JSB.2012.11.003
Abstract: Selenomethionine labeling is the most common technique used in protein crystallography to derivatize recombinant proteins for experimental phasing using anomalous scattering at tunable synchrotron beamlines. Recently, it has been shown that UV radiation depletes electron density of selenium atoms of selenomethionine residues and that UV radiation-damage-induced phasing (equivalent to single isomorphous replacement) protocol can be applied to calculate experimental phases. Here we present the straightforward integration of a UV source with an in-house diffractometer. We show how this setup can extend the capabilities of a sealed tube X-ray generator and be used for experimental phasing of selenium-labeled proteins.
Publisher: Cold Spring Harbor Laboratory
Date: 19-06-2019
DOI: 10.1101/677344
Abstract: Using mRNA-Seq and de novo transcriptome assembly, we identified, cloned and characterized nine previously undiscovered fluorescent protein (FP) homologs from Aequorea victoria and a related Aequorea species, with most sequences highly ergent from avGFP. Among these FPs are the brightest GFP homolog yet characterized and a reversibly photochromic FP that responds to UV and blue light. Beyond green emitters, Aequorea species express purple- and blue-pigmented chromoproteins (CPs) with absorbances ranging from green to far-red, including two that are photoconvertible. X-ray crystallography revealed that Aequorea CPs contain a chemically novel chromophore with an unexpected crosslink to the main polypeptide chain. Because of the unique attributes of several of these newly discovered FPs, we expect that Aequorea will, once again, give rise to an entirely new generation of useful probes for bioimaging and biosensing.
Publisher: Public Library of Science (PLoS)
Date: 02-11-2020
DOI: 10.1371/JOURNAL.PBIO.3000936
Abstract: Using mRNA sequencing and de novo transcriptome assembly, we identified, cloned, and characterized 9 previously undiscovered fluorescent protein (FP) homologs from Aequorea victoria and a related Aequorea species, with most sequences highly ergent from A . victoria green fluorescent protein (avGFP). Among these FPs are the brightest green fluorescent protein (GFP) homolog yet characterized and a reversibly photochromic FP that responds to UV and blue light. Beyond green emitters, Aequorea species express purple- and blue-pigmented chromoproteins (CPs) with absorbances ranging from green to far-red, including 2 that are photoconvertible. X-ray crystallography revealed that Aequorea CPs contain a chemically novel chromophore with an unexpected crosslink to the main polypeptide chain. Because of the unique attributes of several of these newly discovered FPs, we expect that Aequorea will, once again, give rise to an entirely new generation of useful probes for bioimaging and biosensing.
Publisher: Springer Science and Business Media LLC
Date: 02-12-2020
Publisher: Cold Spring Harbor Laboratory
Date: 23-05-2023
DOI: 10.1101/2023.05.23.541926
Abstract: The marine cyanobacterium Prochlorococcus is a main contributor to global photosynthesis, whilst being limited by iron availability. Cyanobacterial genomes typically encode two different types of FutA iron binding proteins: periplasmic FutA2 ABC transporter subunits bind ferric (Fe 3+ ), while cytosolic FutA1 binds ferrous (Fe 2+ ). Owing to their small size and their economized genome Prochlorococcus ecotypes typically possess a single futA gene. How the encoded FutA protein might bind different Fe oxidation states was previously unknown. Here we use structural biology techniques at room temperature to probe the dynamic behavior of FutA. Neutron diffraction confirmed four negatively charged tyrosinates, that together with a solvent molecule coordinate iron in trigonal bipyramidal geometry. Positioning of the positively charged Arg103 side chain in the second coordination shell was consistent with an overall charge-neutral ferric binding state in structures determined by neutron diffraction and serial femtosecond crystallography. Conventional rotation X-ray crystallography using a home source revealed X-ray induced photoreduction of the iron center with observation of the ferrous binding state here, an additional positioning of the Arg203 side chain in the second coordination shell maintained an overall charge neutral ferrous binding site. Room temperature dose series using serial synchrotron crystallography and an XFEL X-ray pump-probe approach capture the transition between ferric and ferrous states, revealing how Arg203 operates as a switch to accommodate the different iron oxidation states. This switching ability of the Prochlorococcus FutA protein may reflect ecological adaptation by genome streamlining and loss of specialized FutA proteins. Oceanic primary production by marine cyanobacteria is a main contributor to carbon and nitrogen fixation. Prochlorococcus is the most abundant photosynthetic organism on Earth, with an annual carbon fixation comparable to the net global primary production from agriculture. Its remarkable ecological success is based on the ability to thrive in low nutrient waters. To manage iron limitation, Prochlorococcus possesses the FutA protein for iron uptake and homeostasis. We reveal a switch in the FutA protein that allows it to accommodate binding of iron in either the ferric (Fe 3+ ) or ferrous (Fe 2+ ) state using structural biology techniques at room temperature and provide a plausible mechanism for FutA as a bifunctional redox state sensing protein.
Location: No location found
No related grants have been discovered for Antoine Royant.