As has been often noted about a number of topics, one’s biases will always skew one’s perspective.
On the one hand, we have this very interesting paper where the authors suggest correlated motions in ubiquitin over a distance of ~ 15 Angstroms (1.5 nm) based on further squeezing information from previously acquired NMR data with the help of computational methods. On the other hand, there is this other very intriguing paper where the authors put forth using gadolinium tags as a way to obtain structural constraints in proteins on the order of ~ 6 nm (60 Angstroms) via ESR/EPR techniques.
In the former, we’re looking at proposed long-distance correlations based on a bunch of relatively weak, short-range interactions (NOEs and RDCs), while in the latter we have nanometer-scale distance constraints being derived from a technique that is well matched to determining distances at the nanoscale. I figure the astute reader can figure where I stand on each given my tone.
Suffice it to say, it’s the reason why I’ve recently developed an interest in 19F NMR (oh, to work with a nucleus that has a decent gyromagnetic ratio and isn’t as common as protons in biological materials!), for one, as well as metal binding tags for paramagnetic relaxation enhancement studies.
In other news, my resolution for the second half of 2011 is to always try and work in a mention of the Helmholtz free energy into each discussion I am involved in that touches upon thermodynamics, as I think far too many chemists have gotten comfortable in their Gibbsian-oriented world.
I suppose this is one of those “it was bound to happen” things – one of the summer undergraduates who is in my lab at my current institution mentioned that the undergrad biochem lab uses a hexahistidine-tagged protein for overexpression & purification. I of course remember having to prep and subsequently grind up giant amounts of animal muscle to extract a protein in my undergrad biochem lab. I feel slightly dusty.
With that observation, I will call this blog post to an end.
9 hours ago