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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: "VAN RAAIJ , MARK JOHAN" mjvanraaij {- at -} CNB {- dot -} CSIC {- dot -} ES Date: 2012-03-07 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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