Quick navigation: Home   |    Site Map   ||    References   |    Biography   ||    Copyright   |    Other copyright   |    Contact us   |    Advert   |   
 

Re: [ccp4bb] Vapor diffusion calculator - better measure it !
- Protein crystallography

Main steps:

   - Protein purification
   - Crystallisation

Special:

   - Programs for crystallography
   - X-ray detectors

Basic tutorials:

   - Chemistry
   - Protein
   - Peptide
   - Amino Acids

Xtal community:

   - CCP4BB

CCP4bb navigation

CCP4bb <-- 1999 <-- November 1999 <-- 30 November 1999
Previous message:
Subject: Re: Vapor diffusion calculator
From: Jose Antonio Cuesta Seijo jose {- at -} KEMI {- dot -} KU {- dot -} DK
Date: 2010-02-03		Next message:
Subject: BCA/CCP4 XVII Summer School in Protein Crystallography 5th-10th Spetember 2010
From: Elspeth Garman elspeth {- dot -} garman {- at -} BIOCH {- dot -} OX {- dot -} AC {- dot -} UK
Date: 2010-02-03


Subject: Re: Vapor diffusion calculator - better measure it !
From: Boaz Shaanan bshaanan {- at -} BGU {- dot -} AC {- dot -} IL
Date: 2010-02-03

Hi,

Instead of calculating the drop composition, there is a simple device, refractometer,  which you can  use to measure the actual composition of the drop (based on the refraction indices of the components). Some of us even used it in the old days. It's possible that with nano-size drops some tricks will have to be applied though.

  Cheers,

            Boaz
----- Original Message -----
From: Jacob Keller
Date: Wednesday, February 3, 2010 0:34
Subject: [ccp4bb] Vapor diffusion calculator
To: CCP4BB@JISCMAIL.AC.UK

> Dear Crystallographers,
>
> Is anybody aware of a calculator for vapor diffusion experiments
> to plot
> concentrations of various solvent components as a function of
> time? For a
> simple example, what happens when I mix a protein solution
> containing 50mM
> NaCl 1:1 with a reservoir containing 50% MPD but no salt? Where
> is the vapor
> diffusion equilibrium, and how does the drop composition change
> as a
> function of time? More complicated would be experiments
> involving volatile
> components other than water, as I think, for example, ethanol
> would almost
> instantly equilibrate, then the water diffusion would kick in
> over a longer
> time scale. Even more complicated would be pH-dependent
> volatilities such as
> acetate. I don't think this would be impossible to figure out,
> but it would
> be nice if there were a pre-existing tool/server to do such.
>
> Regards,
>
> Jacob Keller
>
>
> *******************************************
> Jacob Pearson Keller
> Northwestern University
> Medical Scientist Training Program
> Dallos Laboratory
> F. Searle 1-240
> 2240 Campus Drive
> Evanston IL 60208
> lab: 847.491.2438
> cel: 773.608.9185
> email: j-keller2@northwestern.edu
> *******************************************
>

Boaz Shaanan, Ph.D.
Dept. of Life Sciences
Ben-Gurion University of the Negev
Beer-Sheva 84105
Israel
Phone: 972-8-647-2220 ; Fax: 646-1710
Skype: boaz.shaanan‎
ProteinCrystallography.org: Copyright 2006-2010 by Quid United Ltd