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ICH2026 @ich2026.bsky.social · Jul 23

We are delighted to confirm that the and Other Redox Metalloenzymes will take place from 26-30 July 2026 at the University of Leicester, UK.

Details of the conference, including regularly updated confirmed speakers, are available on our website (link in bio).

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James Birrell @jamesbirrell.bsky.social · Jun 27

Ok, thanks. Solution potential of the activity assay ought to be pretty negative though, right? 100 mM sodium dithionite at pH 6.8. I’d guess ca. -600 mV vs SHE compared with an eq potential of H2 of ca. -400. So you could have 200 mV of overpotential…

James Birrell @jamesbirrell.bsky.social · Jun 27

I’m also interested in a coordination chemist’s view of the 7 coordinate Fe intermediate. Is there likely to be a low barrier to its formation?

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James Birrell @jamesbirrell.bsky.social · Jun 27

Hi Sven. Interesting paper. You said “no significant extra driving force”…You mean no significant overpotential? What is the overpotential and how did you measure it? Also, is it right that the turnover frequency is less than 1 per second? Any ideas how to make this better?

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Reposted by James Birrell

Leicester Institute for Structural and Chemical Biology @leicstructbio.bsky.social · May 21

Congrats @rmlab.bsky.social and co-authors on "Two-dimensional infrared spectroscopy as a tool to reveal the vibrational and molecular structure of [FeFe] hydrogenases" in Chemical Science pubs.rsc.org/en/content/a...

Two-dimensional infrared spectroscopy as a tool to reveal the vibrational and molecular structure of [FeFe] hydrogenases

[FeFe] hydrogenases are Nature's most efficient catalysts for the cleavage and evolution of molecular hydrogen. Despite decades of research, key aspects of the catalytic cycle and the underlying geome...

pubs.rsc.org

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Reposted by James Birrell

Michael Hurst @chemhurst.bsky.social · May 20

Join us next Tuesday May 27 for a Desktop Seminar on the Chemistry of Inorganic Clusters! Featuring talks and live Q&A from Stephen Ragsdale (University of Michigan) and Patrick Holland (Yale University), this is one you don't want to miss!

Register and find more details rsc.zoom.us/webinar/regi...

Promotional poster for an event from the Royal Society of Chemistry titled "RSC Desktop Seminar: Chemistry of Inorganic Clusters" on Tuesday May 27 at 2pm EDT and 7pm BST

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Reposted by James Birrell

Sven T. Stripp @stripplab.bsky.social · May 22

We probed both directions, and it really seems to be the F-domain that modulates the on/off dynamics. We didn't investigate DdH tho...

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Reposted by James Birrell

Sven T. Stripp @stripplab.bsky.social · May 22

We have positions for pCNF SDM of CpI in a recent grant application... Very encouraging to see Kylie's data!

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James Birrell @jamesbirrell.bsky.social · May 22

Presumably, only reduced ferredoxin binds to *oxidised* hydrogenase (during proton reduction)? Meanwhile oxidised ferredoxin should bind to reduced hydrogenase (during hydrogen oxidation)? I guess I need to read the paper…nice work! Any plans to engineer pCNF into CpI?

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Reposted by James Birrell

Sven T. Stripp @stripplab.bsky.social · May 21

We believe that these protein-protein-interactions propell fast & repeated one-electron-transfer reactions, driving multi-electron redox catalysis with a one-electron mediator. In hydrogenase, and other oxidoreductases as well.
Find all the details in the paper:
pubs.rsc.org/en/content/a...

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Reposted by James Birrell

Sven T. Stripp @stripplab.bsky.social · May 21

Uli's brilliant microscale thermophoresis experiments show that *only* reduced ferredoxin binds to hydrogenase, which facilitates assigning the secondary structural changes to redox changes and a shift from an "attractive" to a "repulsive" configuration.

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Reposted by James Birrell

Sven T. Stripp @stripplab.bsky.social · May 21

Infrared difference spectra reveal that the reduction of ferredoxin is accompanied with larger secondary structural changes - clearly associated with the "F-domain" of [FeFe]-hydrogenase, as reference experiments with "minimal hydrogenase" CrHydA1 lack this spectral feature.
A surprise‼️

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Reposted by James Birrell

Sven T. Stripp @stripplab.bsky.social · May 21

Interestingly, in the ferredoxin from C. pasteurianum, reduction alone does *not* affect the nitrile frequency. Only in complex with [FeFe]-hydrogenase CpI, redox changes affect the artificial amino acid...

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Reposted by James Birrell

Sven T. Stripp @stripplab.bsky.social · May 21

Ross @milton-group.bsky.social came up with a very similar idea: how about introducing cyanophenylalanine to a (bacterial) ferredoxin that binds two [4Fe-4S] clusters?
One might learn where the electron resides as most ferredoxins are considered one-electron redox mediators... 🧵

Sven T. Stripp @stripplab.bsky.social · May 21

First off, let me highlight recent work from Vincent et al.: the authors modified plant ferredoxin with cyanophenylalanine and succeeded in measuring FeS-redox-dependent nitrile band shifts in the IR spectra.

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Reposted by James Birrell

bioinorgchemuw.bsky.social @bioinorgchemuw.bsky.social · May 21

"redox-dependent nitrile band shifts" 🤩

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Reposted by James Birrell

Sandy Kilpatrick @sandykilla.bsky.social · May 21

Lovely stuff Zehui et al.!

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Reposted by James Birrell

Sven T. Stripp @stripplab.bsky.social · May 21

Applying this genetic approach to [FeFe]-hydrogenase, the nitrile band allows probing the FeS cluster redox states AND the H-cluster. This will be a powerful tool in other FeS proteins as well!
doi.org/10.1002/cbic...

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Reposted by James Birrell

Sven T. Stripp @stripplab.bsky.social · May 21

First off, let me highlight recent work from Vincent et al.: the authors modified plant ferredoxin with cyanophenylalanine and succeeded in measuring FeS-redox-dependent nitrile band shifts in the IR spectra.

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Reposted by James Birrell

Sven T. Stripp @stripplab.bsky.social · May 21

Who's ready to talk about ferredoxin?

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James Birrell @jamesbirrell.bsky.social · May 14

3 does EB. And EB is my thing now 🤷‍♂️

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James Birrell @jamesbirrell.bsky.social · May 14

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Reposted by James Birrell

Rodriguez-Macia Lab @rmlab.bsky.social · May 11

It is a real pleasure to collaborate with you guys! 😊

James Birrell @jamesbirrell.bsky.social · May 10

Thanks to Marius Horch and the rest of his awesome team, especially Cornelius Bernitzky and Yvonne Rippers. I also want to thank @rmlab.bsky.social for help with preparation of beautiful [FeFe] hydrogenase samples.

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Reposted by James Birrell

Rodriguez-Macia Lab @rmlab.bsky.social · May 11

Very happy to see this out! Take a look at this interesting paper on the application of 2D IR to [FeFe] hydrogenases 👇

James Birrell @jamesbirrell.bsky.social · May 10

Out now in @chemicalscience.rsc.org:

We apply 2DIR spectroscopy to study [FeFe] hydrogenase for the first time. Check it out!

pubs.rsc.org/en/content/a...

Two-dimensional Infrared Spectroscopy as a Tool to Reveal the Vibrational and Molecular Structure of [FeFe] Hydrogenases

[FeFe] hydrogenases are Nature’s most efficient catalysts for the cleavage and evolution of molecular hydrogen. Despite decades of research, key aspects of the catalytic cycle and the underlying geome...

pubs.rsc.org

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James Birrell @jamesbirrell.bsky.social · May 10

So many states 🤩

James Birrell @jamesbirrell.bsky.social · May 10

I’d argue that in most cases it is inferred. Mutagenesis studies are quite clear for some states, and for the COs isotope exchange helps. But the terminal COs show strong coupling. I think 2DIR is pretty useful at being able to tackle much of this without needing to manipulate the system.

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