Dear Garib,

 

thank you for the quick response despite (or because of) the holidays. I’ll
try to summarize because I am not sure I understand yet, and it might be
useful for all :

 

Ø  Partial structure mask bulk solvent parameters. Mask bulk solvent B value
is in addition to protein B value.

 

Not quite clear what you are saying here – how does that answer what the
‘Overall’ means versus the ‘Partial’? (some guessing below)

 

Ø  Full scaling is like this:

 

Fscaled = scale_protein exp(-B s^2/4) exp(-s^T U s) (F_protein + scale_mask
exp(-B_mask s^2/4) Fmask) (1-scale_babinet exp(-B_babinet s^2/4))

 

Ok then I see that I can use either _mask or _babinet terms because only one
set of terms is in effect if the other one is zero. If I turn both off, I
get basic k, B scaling, plus anisotropic B correction. Makes perfect sense. 

 

Based on that I will try to determine which  line in the printout is
actually the bulk solvent contribution. For the ‘Partial structure’ part: 

Partial structure    1: scale =    0.375, B  =  24.388 

If I recall correctly, for the flat bulk solvent model the scale_mask and
B_mask are generally in the order of 0.4 and 40AA, so then this ought to be
scale_mask and  B_mask of the solvent contribution? Yes? No? Now for

Overall               : scale =    0.891, B  =  -0.266

Now it gets interesting: what is this in terms of the above equation? I
don’t seem to be able to factor out a single overall scale and B correction
from your eqn, but it sure looks like a correction term from bulk to be
applied to the overall k and B…. Can you clarify please?

Ø  Current version of refmac does not calculate Wilson B value

I think we can get that readily from say truncate. But that won’t be in the
PDB REMARK 3 then…

 

Ø  Note: Overall Bvalue may correspond to residual overall B value if you
are using TLS refinement

 

Understood.

 

Ø  If you use simple scaling then mask solvent is still on.

 

Yes – that is consistent with the doc.

Ø  You can turn it off by "Calculate the contribution of from the solvent
region"

 

Yes, that can be done by unclicking the box "Calculate the contribution from
the solvent region". Handy if one needs to check certain things…

 

Ø  To turn Babient's bulk solvent you need to use Babinet's scaling instead
of simple.

 

Yep, understood.

 

Thx, BR

 

From: Garib Murshudov [mailto:[email protected]] On Behalf Of Garib
N Murshudov
Sent: Thursday, December 29, 2011 4:47 PM
To: [email protected]
Cc: [email protected]
Subject: Re: [ccp4bb] refmac Bsol

 

Partial structure mask bulk solvent parameters. If you use simple scaling
then mask solvent is still on. You can turn it off by "Calculate the
contribution of from the solvent region"

 

To turn Babient's bulk solvent you need to use Babinet's scaling instead of
simple.

 

I hope it helps

 

regards

Garib

 

 

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