Re: [ccp4bb] phasing power ofatoms

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CCP4bb <-- 2007 <-- March 2007 <-- 28 March 2007

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Subject: Re: Valid to stop Refmac after TLS refinement?
From: "NM Burton, Biochemistry" Nick {- dot -} Burton {- at -} BRISTOL {- dot -} AC {- dot -} UK
Date: 2007-03-28

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Subject: Re: phasing power ofatoms
From: Bernhard Rupp bernhardrupp {- at -} SBCGLOBAL {- dot -} NET
Date: 2007-03-28

Subject: Re: phasing power ofatoms
From: Ethan Merritt merritt {- at -} U {- dot -} WASHINGTON {- dot -} EDU
Date: 2007-03-28

On Wednesday 28 March 2007 08:18, Jim Pflugrath wrote:
> Ethan, very nice web page. I like the discussion of required signal with
> respect to one's diffraction experiment and counting statistics in the
> results page.
>
> I will use this in my lecture tomorrow on SAD/MAD phasing.
>
> Do you mind putting Sulfur as one of the radio buttons?

I don't think that would make any sense. The radio buttons are for the
theoretical f'/f" values at the absorption edge, but it is rather unlikely
that anyone is actually collecting data at the S absorption edge.
Instead you should use the accompanying tool
http://skuld.bmsc.washington.edu/scatter/AS_form.html
to determine the f' and f" terms from S at whatever wavelength you
will be using, and type those into the form.

> Also, do you mind putting 1.5418 A and 2.29 A as wavelengths among your
> edge radio buttons?

Are you still talking about the AS_signal page, or have you switched
to talking about one of the other web pages on the site?
The "edge buttons" on the AS_signal page fill in typical f' and f"
for an arbitrary element at is own K or L edge.

Selecting a fixed wavelength doesn't make sense in this context.
I'd have to add a separate section in the form that takes
both an element and a wavelength as input, and generates theoretical
(as opposed to experimental) f' and f" values. That is certainly
possible, but won't be there in time for your lecture tomorrow :-)

Ethan

> Thanks! Jim
>
> On Wed, 28 Mar 2007, Ethan A Merritt wrote:
>
> > On Wednesday 28 March 2007 07:35, Joyce, Gordon M.(NIH/NIAID) [F] wrote:
> >>
> >> I would like to know the phasing power of different heavy atoms ie how
> >> many seleniums per 10 kDa would be good enough to solve the structure. I
> >> wonder is there a good website or some useful publications that people
> >> know of, that would give this information, not just for Selenium but for
> >> other atoms as well.
> >
> > http://skuld.bmsc.washington.edu/scatter/AS_signal.html
> >
> >
> > --
> > Ethan A Merritt
> > Biomolecular Structure Center
> > University of Washington, Seattle 98195-7742
> >
>

--
Ethan A Merritt Courier Deliveries: 1959 NE Pacific
Dept of Biochemistry
Health Sciences Building
University of Washington - Seattle WA 98195-7742

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CCP4bb <-- 2007 <-- March 2007 <-- 28 March 2007

Previous message:
Subject: Re: Valid to stop Refmac after TLS refinement?
From: "NM Burton, Biochemistry" Nick {- dot -} Burton {- at -} BRISTOL {- dot -} AC {- dot -} UK
Date: 2007-03-28

Next message:
Subject: Re: phasing power ofatoms
From: Bernhard Rupp bernhardrupp {- at -} SBCGLOBAL {- dot -} NET
Date: 2007-03-28