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Re: [ccp4bb] How to reduce no. of overlaps |
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CCP4bb navigationCCP4bb <-- 1999 <-- November 1999 <-- 30 November 1999Subject: Re: How to reduce no. of overlaps From: Frank von Delft frank {- dot -} vondelft {- at -} SGC {- dot -} OX {- dot -} AC {- dot -} UK Date: 2012-03-07 Yes... quite. Thanks! (Beam, rotation axis... how can you expect me to keep all these new-fangled inventions apart?!) On 07/03/2012 07:33, VAN RAAIJ , MARK JOHAN wrote: > typo correction, you'll want the long axis parallel to the rotation > axis, not to the beam. > Mark > > Quoting Frank von Delft: > >> You probably have to tilt your crystal, so that the long axis is >> parallel to the beam. We do this routinely: cut a plastic pipette >> tip to have a sharp point, then push the loop where it attaches to >> the pin, to bend the crystal itself. >> >> You have to identify from your diffraction whether the long axis is >> pointing through the face or the edge of the loop. As it's P6, >> chances are it's through the face, because long-axis P6 tends to >> make flat hexagons which lie flush with the face. So you have to >> bend so the face of the loop upwards. >> >> You'll have to practice this first, though, so put up an empty loop. >> Top tips: >> * Don't breathe! You'll blow the cryostream away. >> * Bend the loop towards (rather than away from) the rim edge of >> the pin to which it's glued. >> * Don't breathe! >> * Practise practise practise. >> >> >> Another thing: most in-house sources allow you to reduce divergence >> of the beam. You lose intensity, but no matter, just expose longer. >> That also improves overlap. >> >> Cheers >> phx >> >> >> >> On 07/03/2012 04:56, Dipankar Manna wrote: >>> Dear Crystallographers, >>> >>> I am working on a protein having SG P6, the cell parameters are a= >>> 79, b= 79, c= 325. The crystals are forming in big size and with >>> very good shape. It also diffracting very well in Home source >>> facility both in terms of resolution and intensity. But the only >>> problem is the number of overlaps. Its showing much more than the >>> good spots. As a result the completeness is showing maximum up to >>> 65% even after collecting 180 degrees. I am unable to get a >>> complete data. I tried with reducing the oscillation angel to 0.3 >>> degree/0.5 degree but it did not improve that much. Please give me >>> some suggestions. >>> >>> Regards, >>> >>> Dipankar >>> >>> /Dipankar Manna/ >>> >>> */Aurigene Discovery Technologies Limited,/* >>> >>> /#39-40 KIADB Industrial Area, Electronic City, Phase II,/ >>> >>> /Hosur Road, Bangalore- 560 100, India/ >>> >>> /Cell: +91-9538631469 // Office Ph : +91 80-66204422 (Extn: 398) >>> Email ID: dipankar_m@aurigene.com/ >>> >>> >>> ------------------------------------------------------------------------ >>> >>> This e-mail and any files transmitted with it are for the sole use >>> of the intended recipient(s) and may contain confidential and >>> privileged information.If you are not the intended recipient, >>> please contact the sender by reply e-mail and destroy all copies of >>> the original message.Any unauthorized review, use, disclosure, >>> dissemination, forwarding,printing or copying of this email or any >>> action taken in reliance on this e-mail is strictly prohibited and >>> may be unlawful. >>> >>> Visit us at http://www.aurigene.com > > > Mark J van Raaij > Laboratorio M-4 > Dpto de Estructura de Macromoléculas > Centro Nacional de BiotecnologÃa - CSIC > c/Darwin 3, Campus Cantoblanco > 28049 Madrid > tel. 91 585 4616 > email: mjvanraaij@cnb.csic.es > CCP4bb navigationCCP4bb <-- 1999 <-- November 1999 <-- 30 November 1999 |
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