Re: [ccp4bb] DNA binding protein

- Protein crystallography

Main steps:

- Protein purification
- Crystallisation

Special:

- Programs for crystallography
- X-ray detectors

Basic tutorials:

   - Chemistry
   - Protein
   - Peptide
   - Amino Acids

Xtal community:

- CCP4BB

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CCP4bb <-- 1999 <-- November 1999 <-- 30 November 1999

Previous message:
Subject: Re: Pictures of DDM crystals?
From: Joe gchen2 {- at -} GMAIL {- dot -} COM
Date: 2009-08-10

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Subject: Re: DNA binding protein
From: Chun Luo chun {- at -} ACCELAGEN {- dot -} COM
Date: 2009-08-10

Subject: Re: DNA binding protein
From: Dima Klenchin klenchin {- at -} FACSTAFF {- dot -} WISC {- dot -} EDU
Date: 2009-08-10

> I had a simple question about DNA binding protein. Is there an
> easy way to detect if your heterologously expressed protein is bound to
> DNA post purification.

Yes. UV absorbance. DNA absorbs UV strongly, proteins do not. DNA absorbs
260 more thn 280, the opposite is true for proteins. In fact, it's always a
good idea to check 260/280 ratio because quite frequently even non-DNA
binding proteins purified by a single tag affinity chromatography contain
enough DNA to skew estimation of protein concentration from 280 nm
absorbance by several fold (9X in one case of my personal experience).

>Also is there an easy way to strip the protein of DNA without any damage
>done to the protein in doing so.

No generic solution. Greatly depends on the protein and its properties.

Dima

CCP4bb navigation

CCP4bb <-- 1999 <-- November 1999 <-- 30 November 1999

Previous message:
Subject: Re: Pictures of DDM crystals?
From: Joe gchen2 {- at -} GMAIL {- dot -} COM
Date: 2009-08-10

Next message:
Subject: Re: DNA binding protein
From: Chun Luo chun {- at -} ACCELAGEN {- dot -} COM
Date: 2009-08-10