Re: [ccp4bb] screw axes /system. absenses and phaser/MR solutions

2018-08-10 Thread Phil Evans
Just to be clear, the Pointless default setting (“CELL-BASED”), which has a On 10 Aug 2018, at 08:29, Kay Diederichs > wrote: > > Tommi, > > one aspect that may be confusing is that XDS and POINTLESS by default have a > different way to describe the setting of orthorhombic space groups with 1

Re: [ccp4bb] screw axes /system. absenses and phaser/MR solutions

2018-08-10 Thread Eleanor Dodson
These problems are a pain! My (half-baked) thoughts 0) Yes - get rid of all junk images etc and inspect the frames - we have had a case where MR would not work for the "best" crystal as processed by XDS, but when we looked at the images there was clear streaking and other technical problems.

Re: [ccp4bb] screw axes /system. absenses and phaser/MR solutions

2018-08-10 Thread Kay Diederichs
Tommi, one aspect that may be confusing is that XDS and POINTLESS by default have a different way to describe the setting of orthorhombic space groups with 1 or 2 screw axes This seems relevant for this particular project, and is discussed in

Re: [ccp4bb] screw axes /system. absenses and phaser/MR solutions

2018-08-09 Thread Eleanor Dodson
Well that is pretty obviously P 2 21 2 - h 0 0 and l 0 0 are obviously present.. The 0 k 0 absences could be generated by a nc translation of x, 1/2, z - do you have that? Twinning is unusual in P2/mmm but possible of course - can you send the pointless log file? Eleanor On 9 August 2018

Re: [ccp4bb] screw axes /system. absenses and phaser/MR solutions

2018-08-09 Thread Kajander, Tommi A
Hi Tim - There are reflections in all directions and only one clearly has systematic absenses. Although only few seem to be present in one direction (But thats the h00 direction here + all are present though) -phaser finds with same data P22121 as the strongest solution (few reflections are

Re: [ccp4bb] screw axes /system. absenses and phaser/MR solutions

2018-08-09 Thread Tim Gruene
Dear Tommi, did you check whether you collected any reflections at all that should be absent for the second screw axis? If there are non - which could easily happen with low resolution, incomplete data - pointless and XDS might be conservative and not estimate the likelihood for the second

Re: [ccp4bb] screw axes /system. absenses and phaser/MR solutions

2018-08-08 Thread Eleanor Dodson
l quality in some > directions - overall data is not great... > > Best, > Tommi > > > Kohteesta: Eleanor Dodson > Lähetetty: keskiviikko 8. elokuuta klo 17.46 > Aihe: Re: [ccp4bb] screw axes /system. absenses and phaser/MR solutions > Vastaanottaja: Kajander, Tommi A &

Re: [ccp4bb] screw axes /system. absenses and phaser/MR solutions

2018-08-08 Thread Kajander, Tommi A
Lähetetty: keskiviikko 8. elokuuta klo 17.46 Aihe: Re: [ccp4bb] screw axes /system. absenses and phaser/MR solutions Vastaanottaja: Kajander, Tommi A Kopio: CCP4BB@JISCMAIL.AC.UK How many molecules in the asymmetric unit? and is there a non-crystallographic translaton? Eleanor On 8 August 2018

Re: [ccp4bb] screw axes /system. absenses and phaser/MR solutions

2018-08-08 Thread Eleanor Dodson
How many molecules in the asymmetric unit? and is there a non-crystallographic translaton? Eleanor On 8 August 2018 at 15:29, Kajander, Tommi A wrote: > Hi, > Any clues why the followting happens: pointless (and just looking at the > XDS output) clearly tells there is one screw axis in

[ccp4bb] screw axes /system. absenses and phaser/MR solutions

2018-08-08 Thread Kajander, Tommi A
Hi, Any clues why the followting happens: pointless (and just looking at the XDS output) clearly tells there is one screw axis in P-ortorhombic (P2212) yet phaser gives the best Z-scores in P22121. (...I suspect this may be to do with twinning - might be monoclinic twiined still though now