Size is everything

Flicking through the RSS for my favourite journal just now, I noticed that of the dozen or so crystal structure papers (out of the thirty or so new papers), two sets of authors felt it necessary to state the structural resolution in the paper’s title. They were 1.6 and 1.8 Ångstrom structures; not too shabby, I guess. A third authorial team were moved to begin their title High-Resolution Structure of … and the abstract claims 1.1 Å.

Now, resolution is one metric used to judge crystal structures: more objective information is obtained from the Free R , geometry deviations and other parameters . The ‘resolution’ does tell us what me might expect to ‘see’, however, and appears incredibly seductive to the professional scatterbrain.

And there is a bit of a hierarchy. Go to any talk in which there is a crystal structure described, and watch the speaker’s face when it comes to resolution. Although the Free R tells you how good the structure is, all the other crystallographers want to know the resolution. The speaker will mumble if the resolution is higher (i.e. worse) than about 3 Ångstrom, be pretty upbeat if it’s in the range 2.0 – 2.6 Å, and positively beam if the data is better (i.e. lower) than 2 Å. And then there’s the ‘Holy Grail’ of 1 Å structures, with low Free R, which quite frankly are rather neat because you can see that Kekulé was right.

You see the same in papers. A crystallographer with a better than 2 Ångstrom data set will want to skite in the title — and maybe they also wanted to let everyone know that they scored synchrotron time (as ‘in house’ X-Ray sets tend not to allow collection of data at better than ~ 1.8 Å resolution, although yours truly managed 1.6 Å once)01474-2 ).

It’s a matter of pride , I fear.