[sharp-discuss] Question about error in MAD phasing

[Clemens Vonrhein]

Hi Bernhard,

it looks to me as if the data you gave autoSHARP is somehow wrong. The
step it is complaining tries to convert the DANO (ie anomalous
differences) to E-values for use in heavy atom detection. Check the
following:

1. what is the completeness of your anomalous data overall (but
   especially in the highest and the lowest resolution bin)

2. if something went wrong: do a 'mtzdmp' on your MTZ file(s) after
   TRUNCATE to see if there is actually some data available for DANO.

My guess is that the completeness of your data is rather low in the
high resolution (1.75A) bit. And ECALC needs a certain amount of
reflections per bin. You could try to give autoSHARP only data within
a sensible resolution limit. This can be done in two ways:

  a) just prepare MTZ files in the desired resolution range
     (e.g. using mtzutils)

  b) specify yourself as EXPERT user (in the SHARP Preferences) and
     you can give explicitely the resolution range you want to
     use. You could try gicing e.g. 2.0 as high resolution limit.

If you tell me a bit more about your data I could try to catch this
error automatically - and accomodate for it automatically in
autoSHARP.

I hope that helps.

Cheers

Clemens


On Tue, Oct 22, 2002 at 09:44:02AM +0200, Bernhard Spingler wrote:
> Hi all,
> 
> I collected MAD data on Re, integrated with Mosflm, used Scala and Truncate
> to prepare the data for sharp.
> 
> I get the following error, when running sharp on the 2 wavelength data:
> 
> 
>  ***  Warning
>  From LRASSN : Column type for program label FP does not match - file label
> is DPHM_w1
> 
>                 ECALC:  **** ERROR - Empty shell - increase NSHELL.
>                                         
>      autoSHARP(ECALC) project MAD set 1 id w1 ano                          
> 
> 
>  SPACE GROUP         =    5  C2        
>  MAX RESOLUTION      =     1.754
>  REFLNS/SHELL        =       200
>  NO OF REFLNS WANTED =      5737
> 
>   (Q)QOPEN: file opened on unit  2      Status: UNKNOWN
>  Logical Name: HKLOUT      Filename: ECALC/ecalc_w1_ano.mtz
> 
>  * Output Program Labels :
>  
>  F E SIGE F2OR E2OR
>  
>  * Output File Labels :
>  
>  H K L FM SIGFM FPHM_w1 SIGFPHM_w1 DPHM_w1 SIGDPHM_w1 FPHM_w2 SIGFPHM_w2
> DPHM_w2
>  SIGDPHM_w2 FreeR_flag FM2OR F_w1_ano E_w1_ano SIGE_w1_ano F2OR_w1_ano
>  E2OR_w1_ano
>  
>  * Output File Column Types :
>  
>  H H H F Q F Q D Q F Q D Q I F F F Q J J
>  
>  $TEXT:Number and range of reflections: $$ comment $$ 
>        0 REFLNS (Excluding missing ones),  MAX F =        0.
> 
>  MIN, MAX S =  100.0000    0.0000     RESOLUTION LIMITS =     0.100       inf
>  $$
> 
>     SHELL   NO OF REFLS   RESOLUTION    MEAN DSTAR^3     MEAN F^2
> SMOOTHED F^2    MEAN E^2-1     MEAN(E^2-1)^2
> 
>  ECALC:  **** ERROR - Empty shell - increase NSHELL.
>  Times: User:       0.2s System:    0.0s Elapsed:    0:01
> 
> Thanks for any help in adavance
> 
> Best regards
> 
> Bernhard 
> 
> *****************************
> 
> Dr. Bernhard Spingler
> University of Zuerich
> Inorganic Chemical Institute
> Winterthurerstr. 190
> CH 8057 Zuerich
> Switzerland
> 
> 
> 
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