Hi,

the two macros that I wrote are for measuring RDCs only - either from
non-decoupled spectra with doublets or from IPAP type spectra (it should
be possible to extraxct J couplings from COSY aswell). They stopped
working in the latest release I think, but you only need to
change a few lines - I'll send a patched up version. I'll try to
improve the Help too. I followed the path of least resistance in getting
couplings out of analysis (see below), so I didn't make very good
use of the data model - hopefully the macros will save someone work in
the meantime though.

Because the RDC experiment prototypes didn't exist I couldn't get the
atoms out of the data model, so you have to enter the atom names for a set
of RDC experiments (because e.g. for proteins you might be looking at a 15N
HSQC-like spectrum in which the splitting corresponds to a CaC' coupling
from the previous residue - the magnetization transfer pathway needs to
be defined so you can pick out the right atoms). Without the proper
atoms to go with the calculated couplings I didn't try to write anything
to store them back in the project either, but that shouldn't be too
difficult. With the RDCs stored in the project it would be much easier to
implement a histogram plotting macro, maximum likelihood or even (with
structures) SVD to obtain estimates for the alignment tensor parameters.
Would be really helpful if you're using SANI in xplor/aria for instance. My
macro requires you to enter a scaling factor for each type of coupling when
you have different types (to scale to e.g. NH) for the purposes of the
structure calculation, but that makes it more versatile if you've
implemented the experiment in a way that scales the coupling e.g. to
reduce the period during which the coupling is sampled to reduce
relaxation losses. To determine errors the best practice would be to repeat
all your measurements, but using the signal to noise and linewidth you can
get a good estimate - the only problem is, peaks don't have an
associated linewidth or peak picking error at the moment, so my macro
just asks for LW and S/N for a given spectrum and assumes all have the
same error - it probably doesn't cause huge problems, but it isn't the best
you can do.

Hope that helps - let me know if I can be of any assistance.

Cheers,

Graeme

Quoting Murali Vadivelu <[log in to unmask]>:

> Dear Developers,
>
> How does RDCs and analysis go together these days, with the plugin of
> course? Is it reasonably mature to avoid using PALES and such for the
> purpose?
>
> Many thanks.
>
> Best regards,
> Murali.