A.742 - From: SMTP%"firstname.lastname@example.org" 20-OCT-1995 16:52:59.05
I am trying to generate a mask using MAMA, of my molecule in its p41212 space group. However, when I get to overlap trim, it seems to not calculate the assymetric unit correctly, and gives the error ERROR --- Not an asymmetric unit ! the output is:
Nr of points in unit cell : ( 1552320) Nr in your asymmetric unit : ( 202300) Nr of symmetry operators : ( 8) Asymm. unit * symm. opers. : ( 1344800)
so it is apparently not multiplying correctly? please can you advise?
From: XRAY::GERARD "Gerard 'CD' Kleywegt" 20-OCT-1995 17:06:41.83
which numbers did you type for overlap origin and overlap extent ? And what is the asu for your spacegroup (0-1 0-1 0-1/8 ?)
If your grid is e.g. 120 * 120 * 160, you would use:
ov ori 0 0 0and:
ov ext 121 121 21(or 122 122 22 to be on the safe side)
From: SMTP%"email@example.com" 20-OCT-1995 18:28:24.26
Thanks for your quick reply, I have set
ov ori 0 0 0 ov ext 85 85 28where my grid is 84 84 220 (whole cell) my asu is 0-1 0-1 0-1/8
So I thought this should be ok.
From: XRAY::GERARD "Gerard 'CD' Kleywegt" 20-OCT-1995 18:40:57.70
The problem is with the C axis grid: 220 is not a multiple of 8 (i presume this gives problems in the FFT in CCP4 as well ??)
Use 216 or 224 instead & it should work (if you use 1/8*224 + 1,2or3 in MAMA)