[phenixbb] Twin refinement issues?

[Peter Zwart]

> this assumes two domains, right?  IIRC, every discussion of twinning i
> have read treats the problem in terms of two domains.  what is the basis
> for only having two domains (besides simplicity)?

The twin law is a rotation operator. the order of that rotation
(2fold, 3 fold, 4 fold, 6fold) determines the number of domains for a
single twin law.

>
> someone mentioned a three-domain twinning problem (maybe ccp4 or phenix
> bb, last week or so) - wouldn't that need "1-alpha-(third domain
> fraction)"?

yes!

P



> -bryan
>
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P.H. Zwart
Beamline Scientist
Berkeley Center for Structural Biology
Lawrence Berkeley National Laboratories
1 Cyclotron Road, Berkeley, CA-94703, USA
Cell: 510 289 9246
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