CBASS is a cyclic nucleotide-based antiviral system in bacteria that is related to cGAS-STING signaling in animals. One of the big questions is how CBASS is activated during phage infection? We made some progress on this during my final year in the Kranzusch lab.
www.biorxiv.org/content/10.6...
A jumbo cyanophage encodes the most complete ribosomal protein set in the known virosphere www.biorxiv.org/content/10.1...
Out now! In collaboration with Leifu Chang, we uncover the molecular and structural underpinnings of CRISPR-Cas12f-like RNA-guided transcription systems!
Links to the published articles:
tinyurl.com/55kpavet
tinyurl.com/sk6djwx3
Previous thread for the preprint:
bsky.app/profile/did:...
Science update from my postdoc Peiyuan Chai - his work βglycoRNA complexed with heparan sulfate regulates VEGF-A signalingβ is now published @nature.com uncovering a new layer or glycoRNA-regulation of growth factor mediated control physiological processes rdcu.be/e1bBX
New #glycotime discovery from @raflynn5.bsky.socialβs lab @bostonchildrens.bsky.social @harvard.edu, cell surface glycoRNA-RBP complexes organized by heparan sulfate PG nanoclusters that modulate VEGF signaling
www.nature.com/articles/s41...
The full biosynthetic pathway is still unknown as far as Iβm aware but probably involves some bonker RIPP enzymes. Another reminder that Nature is the best chemist around
Theyβre also super weird to categorize as molecules. Technically you can end up with two isomers depending on if the Trp-sulfoxide ring is βupβ or βdownβ relative to the rest of the ring but theyβre also not true atropisomers as you canβt heat one to interconvert into the other
Dreams really do come true π I'm extremely excited to be joining the University of Vermont this fall as a Tenure-track Assistant Professor in Chemistry!
A research team has found multiple lineages of archaea that have fully repurposed the TAG stop codon to encode the noncanonical amino acid pyrrolysine. cen.acs.org/biological-c... #chemsky π§ͺ
Today, I'm grateful that Alanna Schepartz is visiting Tufts. Alanna's leadership of @cgemcci.bsky.social has led to impressive advances in genetic code expansion, including recently published work pushing encoding beyond alpha-amino acids.
#ChemSky #ChemChat
www.nature.com/articles/s41...
Iβm a fan of this paper from Gillingham that looks at some macrocyclic DELs as a more standard pick (onlinelibrary.wiley.com/doi/full/10....) and this work on a protein-templated DEL system might be an interesting curveball!
www.nature.com/articles/s41...
Youβve heard of ubiquitination, meet deazaguanylation: Doug Wassarman in our lab discovered phage defense pathways have co-opted Q nucleobase biosynthetic enzymes to catalyze a new form of protein conjugation chemistry @science.org
www.science.org/doi/10.1126/...
βHypervalent iodide giveth and hypervalent iodide taketh awayβ
Well itβs chemistry of course. The reason why organic chemists historically make p-tosylates rather than the simpler benzenesulfonates is that p-tosyl chloride is a cheap byproduct from saccharin synthesis. The ortho isomer is used for saccharin. #chemsky π§ͺ
>1700 examples???
Finally out in Nature Chem Bio:
SNAP-tag2 for faster and brighter protein labeling
www.nature.com/articles/s41...
Thank you Steffi and Veselin.
How do you turn a carbonyl into sulfur?
In this work, Zining from our lab developed a carbonyl-to-sulfur swap enabled by a rationally designed Nβ²-alkyl-hydrazonamide (NAHA) reagent that promotes double C-C bond activation.
www.science.org/doi/10.1126/...
Seems a good time to post the βTop types of med chem papersβ #ChemSky
Yeah itβs currently cold enough in my building (heater is down) that the dmso spontaneously froze when I started pipetting which 100% didnβt help with my 3mm tube problem
Never am I more convinced that I angered an eldritch god in a past life than when Iβm trying to pipette a sample in dmso-d6 into a 3mm NMR tube #chemsky
Ooh I might steal this shade of green yβall useβ¦
I was having a hard time describing how a plate of cultured cells didnβt look healthy to a new undergrad in the lab. He looked at them and said, βoh yeah, the vibes are off.β Thank god for Gen Z.
Check out our latest preprint describing two structures of ribosomes complexed with the two enantiomers of a Ξ²2-hydroxy acid. Our structures show that despite stereochemical differences, both are ultimately well positioned for bond formation within the ribosome!
chemrxiv.org/engage/chemr...
Wait thatβs interesting. Different type of system I think but still very cool. Also I love the phrase βpolymer loreβ
For an article in the 1970s to specify a reagent was βcautiously addedβ is really somethingβ¦
Will update if I can get this route to work π
Amazing!! Thank you!!
Hmm wait that makes sense. Ok I might just push the NaN3 route forward and see if adding an external lewis acid gets me similar reactivity in the aggregate. Worst case scenario I make the lithium azideβ¦
Maybe this is a shout into the void but any thoughts on why someone would choose to use lithium azide over sodium azide to ring open an epoxide? Like every lit precedent cites the same original synthetic route and one group even goes about making LiN3 from NaN3. Kinda at a loss
Oh this wasnβt even the example I was thinking of but you just reminded me of a set of papers I saw that βimprovedβ on a lanthanum triflate catalyzed reaction by switching to Pb(NO3)2
