NMR properties are an important part of the spectroscopic toolbox of ORCA 6 (@faccts-orca.bsky.socialdoi.org/10.1021/acs....#ORCAqc#ORCA6#NMR#ChemSky#CompChem
(2S,3S)-4-Fluorovaline (FVal) is an analogue of valine, where a single CH3 group is substituted by a CH2F group. In the absence of valine, E. coli valyl-tRNA synthetase uses FVal as a substitute, enabling the production of proteins uniformly labeled with FVal. Here, we describe the production and analysis of E. coli peptidyl–prolyl isomerase B where all 16 valine residues have been replaced by FVal synthesized with a 13C-labeled CH2F group. Although the melting temperature is lower by about 11 °C relative to the wild-type protein, the three-dimensional protein structure is almost completely conserved, as shown by X-ray crystallography. The CH2F groups invariably populate staggered rotamers. Most CH2F groups populate two different rotamers. The increased space requirement of fluorine versus hydrogen does not prohibit rotamers that position fluorine next to a backbone carbonyl carbon. 19F NMR spectra show a signal dispersion over 25 ppm. The most high-field shifted 19F resonances correlate with large 3JHF coupling constants, confirming the impact of the γ-gauche effect on the signal dispersion. The present work is the second experimental verification of the effect and extends its validity to fluorovaline. The abundance of valine in proteins and structural conservation with FVal renders this valine analogue attractive for probing proteins by 19F NMR spectroscopy.
The first Quantum Mechanics in Pharma meeting starts today! Don't miss Christoph Riplinger’s (@faccts-orca.bsky.social#ORCAqc#ORCA6#CompChem#QuantumChem#PharmaChem#QMinPharma24#ChemSky
New video on using the GOAT method to find global minima with Orca and XTB, for a corrole dimer. #compchem#chemskyyoutu.be/GvTNg2gKuZc
YouTube video by nicolas N
Save the date! We (@faccts-orca.bsky.social@gdch.bsky.social#GCC2024#ORCA6#CompChem#ChemInformatics#ChemSky
Thanks! I am not yet how to deal with lists, but I hope I did the right think to subscribe. 🙌
It's honestly fun to see the algorithm doing the search - and the results of course 😉