Also MATTPROB indicates 3 or 4 molecules/asu as likely solutions.

http://tinyurl.com/pe2choc

I do not understand why you propose 16 mol/asu?

The entire unit cell would likely be only 8 molecules (2 tetramers)....

BR

-----Original Message-----
From: CCP4 bulletin board [mailto:[log in to unmask]] On Behalf Of Remy Loris
Sent: Sunday, August 17, 2014 4:45 AM
To: [log in to unmask]
Subject: [ccp4bb]

A back of the envellope calculation shows that your asymmetric unit contains most likely 4 molecules with Vm = 2.16 A3/Da, corresponding to 43% solvent. Searching for 16 molecules is thus nonsense.

Remy Loris
Vrije Universiteit Brussel

On 17/08/14 08:54, Avisek Mondal wrote:
> Hello everyone, i am struggling with a problem.. My crystal was
> diffracted at 1.9A in P21 spacegoup with unit cell parameter a=87.7
>
> b=93.9, c=111.78 ,beta=94.98  which contains 16 molecules per
> assymmetric unit (Molecular weight of the Protein+DNA =56 KDa.
>
> actually it is a complex of 40Kda tetramer and 23bpDNA ) .In solution,
> it shows tetrameric in nature The crystal structure of its
>
> homologous structure has been reported earlier (50%identical in amino
> acid seq.) and  it was also a tetramer and its unit cell (also P21)
>
>  was approximately 4 times less than mine. It showed 4 molecules per
> assymmetric unit. I didn't get any  molecular replacement. All
>
> the programms are takings very long time to do it. Although the single
> crystal is  untwinned  i think it is a case of pseudosymmetry.
>
>  Please help me if you have any good suggestion regarding molecular
> replacement other than experimental phasing.
>