Tristan Croll
@crolltristan.bsky.social
1.9K followers 990 following 39 posts
Structural biologist and lover of all things biochemistry. Principal Scientist at Altos Labs. Developer of ISOLDE for macromolecular modelling in cryo-EM and Xtal maps: https://tristanic.github.io/isolde/
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crolltristan.bsky.social
Oooh, I know lots of those!
crolltristan.bsky.social
Possibly the most evergreen Onion article in history: theonion.com/recession-pl...
crolltristan.bsky.social
“What is biology?”
crolltristan.bsky.social
This brings back memories… climbing at Mt Arapiles, near the top-out about 30m off the ground I came across a crack very like this, with an odd white spot deep inside. Got closer to look, and realised it was a teeny tiny pair of fangs… unforgettable moment.
A small, scared bat showing off its fangs.
crolltristan.bsky.social
I’m guessing your problem is the dependency on the “sanity” package. Unfortunately that stopped being maintained a while back, and won’t install in the latest Python version.
Reposted by Tristan Croll
drhorrell.bsky.social
Had a very long social media break after the last #SynchrotronMugMadness and the bird site's decent into horror.

So hello bluesky, I'm a staff structural biologist helping @imperiallifesci.bsky.social solve protein structures with #crystallography and #CryoEM.

Please enjoy these protein crystals 💎
Several microscopic iron containing protein crystals in a variety of cookies (blue, yellow, orange, green)
crolltristan.bsky.social
🎶 When a muppet with teef finds a home on the reef, that’s a moray 🎵
crolltristan.bsky.social
(this is actually the old laptop I used for most of my original work on ISOLDE. Poor little thing… will try to look after it better in future)
crolltristan.bsky.social
Kids were complaining that their gaming laptop was getting a bit sluggish… 😳🤢
A solid wall of accumulated dust. Somewhere underneath it is a laptop cooling fan.
crolltristan.bsky.social
Interviewer: Can you explain this gap on your CV?

Evolutionary biology: Well, yeah… but then I’ll have two *new* gaps you’ll want me to explain.
supersciencegrl.co.uk
Interviewer: Can you explain this gap on your CV?

Chemist: Yeah, that's what's between the HOMO and the LUMO #chemsky
duetosymmetry.com
Interviewer: Can you explain this gap in your resume?

Gravitational-wave astronomer: It depends on the maximum neutron star mass and details of the supernova mechanism ... or it could just be a selection effect

🧪⚛🔭
crolltristan.bsky.social
Could of course fire up a “proper” docking package for that, but often this way seems quicker and easier (and helps get a better feel for the site, to boot). Take out the map, “isolde restrain distances” to maintain local conformation, then just play with it.
crolltristan.bsky.social
Both true. :) Although if it’s a novel ligand (or just something not in the CCD) the first point isn’t such a big issue. I don’t use it *that* often, but I do occasionally use it quickly assess hypotheses (“I wonder if{ligand} might plausibly fit this pocket?”).
Reposted by Tristan Croll
clausenlab.bsky.social
🎄 xmas preprint 🎄 we are excited to share our cryo-EM structure of UBR4 in complex with KCMF1 and CALM1. the PQC ligase forms a massive ubiquitination arena, primed to amplify ubiquitin chains (E4 activity) and boost degradation of defective proteins. www.biorxiv.org/content/10.1...
Architecture of the 1.3 MDa complex of human UBR4 (2 x UBR4/KCMF1/CALM1). Picture shows top and side views of the cryo-EM density map and the modeled structure, colored by protein components and domains.
crolltristan.bsky.social
Still trying to work that out, I’m afraid. While we have some interesting “ISOLDE-adjacent” stuff in the works, my day job currently doesn’t leave a lot of (well… any, really) time free for development of ISOLDE itself. Exploring options to support it in a more sustainable way.
crolltristan.bsky.social
One nice quality-of-life addition: all “open” commands now have an optional “cofr” argument. So for example…

open ligand.mol2 center cofr

or

open {smiles string} from smiles center cofr

… will put the ligand on ISOLDE’s crosshairs ready to move around and merge in.
crolltristan.bsky.social
While I haven’t had a chance to add anything really substantial to ISOLDE, the @www.cgl.ucsf.edu team have added a bunch of great new stuff to ChimeraX itself.
crolltristan.bsky.social
For people who managed to install older versions of ISOLDE into ChimeraX and found they promptly failed… sorry, that’s my fault. I didn’t RTFM about Python’s ‘~=‘ specifier. Thought “~=1.8.rc0” meant “>=1.8.rc0”, ==1.8.* when it actually means “>=1.8.rc0, ==1.*”.

🙃

Anyway, update to fix.
crolltristan.bsky.social
You know what they say about never releasing on a Friday… what does it say about me that I’m releasing on the last Friday before Christmas? 😬

Anyway, ISOLDE builds for ChimeraX 1.9 are now up. Enjoy!
Reposted by Tristan Croll
dereklowe.bsky.social
An interesting finding that some types of HPV infection might be preventing cancer (as opposed to the ones that can cause it).

Also features G.K. Chesterton and a brief cameo by RFK Jr.
HPV Infections: Friend and Foe
www.science.org
crolltristan.bsky.social
Man… the fact that there’s a *second* ring galaxy visible in the gap? The sci-fi story (where these are the still-growing explosions from the past firing of some unimaginably powerful galaxy-killing beam weapon) practically writes itself.
creatorbluesky.bsky.social
Hoag’s Object is a rare ring galaxy located over 600 million light-years from Earth.

A nearly perfect circle full of young blue stars surrounds a spheroid of mostly older red giant stars. In between is a gap that appears almost completely empty.

Delightfully distinctive.

📸 Credit: NASA/STScl/AURA
crolltristan.bsky.social
I’m afraid I honestly don’t remember that. 🤷‍♂️
crolltristan.bsky.social
I remember Jane Richardson and her team doing a fair bit of work trying to sort out “total junk” from “partially correct” down in the very-low-pLDDT regime. Don’t know if/where it was published, though.