RE: [ccp4bb]: RNA crystals

[rbrown7]

Title: Re: [ccp4bb]: RNA crystals

Hi folks,

 

Thanks for your interesting comments about RNA crystallization.

 

Actually I am trying to crystallize the RNA duplex, but the small amount of RNA hairpin present in the sample appears to have come out, with the 1.4M tri-sodium citrate.

 

The RNA has a self-complemantary sequence of course.

 

The crystals are quite dense and very birefringent and diffract to 2.8 angstroms. The small unit cell suggests that only a hairpin could fit in it.

 

I could not find any published report of RNA crystals coming out of tri-sodium citrate. There are no divalent cations or polyamines present.

 

I am very surprised at this crystallization result.

 

Cheers,

 

Ray Brown

Department of Molecular and Cell Biology

University of Connecticut

---

From: Daniel Anderson [mailto:[EMAIL PROTECTED]
Sent: Wed 8/16/2006 8:46 PM
To: Brown,Raymond (BIDMC - Experimental Medicine)
Cc: CCP4 News Group
Subject: Re: [ccp4bb]: RNA crystals

There's a nice article about RNA crystallization:
Golden, Kundrot (2003) Journal of Structural Biology 142, 98-107.
In a fast scan, I don't see mention of citrate ion.

It's amazing what I find in these piles around my desk.

-Dan

On Wed, 16 Aug 2006, William Scott wrote:

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>
>
> It is fairly common to get RNA (or DNA) crystals in high concentrations of
> monovalent cations, including Na+, Li+, and even NH4+.  More surprising to
> us was that several of the ribozymes function quite happily in the
> presence of monovalent cations that were thought to require divalent
> cations for cleaving.
>
> One thing you will want to be aware of is that simple RNA hairpins have a
> high propensity to crystallize as dimeric duplexes with mismatches in the
> middle corresponding to the hairpin region.
>
> The anion is usually not relevant, but in the case of citrate, it can
> chelate Mg++. For that reason, I tend not to use it in screens, but there
> is no particularly fundamental reason why citrate should be unusual, apart
> from that.
>
> HTH,
>
> Bill
>
>
>
> On Wed, 16 Aug 2006 [EMAIL PROTECTED] wrote:
>
> > Hi folks,
> >
> > I appear to have grown some crystals of an RNA hairpin using 1.4 M sodium citrate.
> >
> > Has anybody else out there been able to get crystals of RNA or DNA using sodium citrate as the precipitant ?
> >
> > This result seems to be rather unusual to me.
> >
> > Please get in touch if you know of any similar, successful crystallization conditions.
> >
> >
> > Cheers,
> >
> > Ray
> >
> > email [EMAIL PROTECTED]
> >
> >
>