LLI agree the difference between sd and SigI are a bit obscure. One
referes to the spread of values about your mean I (The Sd of the
reflection distribution)
SigI is derived from the SIGI values estimated by the integration.
There is some description in the CCP4 study weekend article by Phil Evans
/Acta Cryst./ (2006). D*62*, 72-82 [ doi:10.1107/S0907444905036693 ]
Scaling and assessment of data quality
P. Evans
*
*
http://journals.iucr.org/d/issues/2006/01/00/issconts.html
Cant answer the PDB Q - I guess there should be a manual on their web site?
Eleanor
u Yongzhi wrote:
> Hi everyone,
>
> When I scale the data using Scala, I don't know differences between
> _diffrn_reflns.meanI_over_sigI_all 6.5475
> _diffrn_reflns.meanI_over_sd_all 21.3013
> in the statistics. I think that both "sigma" and "sd" have the same
> meaning--"standard deviation". By the way, in the file header of PDB's, what
> are the meanings of the numbers 5 and 1 in the row "HELIX", numbers 0, 1 and
> -1 in the row "SHEET". And in the row "SHEET", what's the meaning of the last
> 6 columns.
> HELIX 1 1 THR A 35 ASP A 37 5 3
>
> HELIX 2 2 SER A 41 TYR A 46 1 6
>
> HELIX 3 3 GLU A 68 ALA A 82 1 15
> SHEET 1 C 6 GLU A 224 ARG A 232 0
>
> SHEET 2 C 6 ILE A 214 GLU A 221 -1 N CYS A 217 O ARG A 229
>
> SHEET 3 C 6 PHE A 183 VAL A 189 -1 N PHE A 187 O LEU A 218
>
> SHEET 4 C 6 VAL A 302 LEU A 309 -1 O ILE A 306 N LYS A 184
>
> SHEET 5 C 6 LYS A 254 HIS A 261 -1 N ILE A 258 O GLY A 305
>
> SHEET 6 C 6 GLU A 280 PRO A 288 1 O ASP A 283 N VAL A 257
>
>
> Thanks
>
> Lu Yongzhi
