Absolutely you should optimise! It's impossible to predict crystal behaviour. I had a 20 A crystal, and I set a new plate in the same reservoir with an additive screen and got a 3A crystal. It was probably a completely different crystal to be honest, lattice, etc, but one never knows, you just have to try. You can also try using the low res crystal as a seed. Plus a million other things.
Paul Steven Miller (PhD)
Postdoctoral Researcher
University of Oxford
Wellcome Trust Centre for Human Genetics
Division of Structural Biology
Roosevelt Drive
Oxford
OX3 7BN
---- Original message ----
>Date: Fri, 2 Mar 2018 17:34:18 -0800
>From: CCP4 bulletin board <[log in to unmask]> (on behalf of Natalia O <[log in to unmask]>)
>Subject: [ccp4bb] does 12 A diffraction worth optimization
>To: [log in to unmask]
>
> Hello,
>
>
>
> I got crystals of protein-nucleic acid complex,
> rod-shape, reproducible, don’t visibly get damaged
> upon freezing; however they gave diffraction only to
> about 12 A. I tried several crystals. My question is
> whether such crystals worth optimization. Clearly a
> 4A diffracting crystal could potentially be
> optimized to 3 – 2.5A, but if the diffraction that
> I am getting now is 12A it could suggest that the
> system is so flexible that getting to 3A with this
> crystal form is not possible at all. I just wonder
> if there is any statistics or a rule of thumb about
> what initial diffraction worth optimization?
>
> Thank you!
>
> -Natalia
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