Re: [ccp4bb] structural homologs as cross seeds
There are many examples where cross-seeding with homologous proteins has worked, both in classical and recent work. You should add seed-stocks from any crystals with significant homology to your routine screening experiments in the first place. The important thing is to use *random *screens at first. This has the effect of giving you new leads and also optimizing the ones that you have (plus you can control the number of crystals per drop). See http://hamptonresearch.com/documents/ramc/RAMC2011_T11_Obmolova.pdf (Omolova and colleagues have examples where complexes were seeded with crystals of one of the components and vice versa.) The excellent review by Stura and co covers most of the theoretical points. (1999). Epitaxial jumps. *J. crystal growth*, *196*(2), 250-260. For practical details see the original paper by D'Arcy (Acta Cryst D: 63.4 (2007): 550-554) and also our paper Random microseeding: a theoretical and practical exploration *Crystal Growth Design* 11.8 (2011): 3432-3441. also http://www.douglas.co.uk/MMS_proc.htm Acoot, this is also the approach to use with your cubic crystals. Don't think about it too much, just try it! The only thing that I can't explain is why this random seeding method, including cross-seeding, is not more well-known. Hope it works Patrick On 27 December 2013 21:03, Mark van Raaij mjvanra...@cnb.csic.es wrote: the differences are likely to be on the protein surface, and these would make the crystal contacts, i.e. it would be unlikely the protein could crystallise in the same crystal habit. Never say never in crystallisation (i.e. try anything), but I would go for other things first like additives, different crystallisation techniques, temperatures, concentrations etc. On 27 Dec 2013, at 20:29, Mahesh Lingaraju wrote: Dear all, I was wondering if it sounds logical to use the crystals from a possible structural homolog as seeds to induce nucleation ? (in terms of overall sequence, the proteins are considerably different but based on sequence alignment and structures from other related proteins, it is highly likely the protein would have the same structure.) Please comment if any of you had experience with this. Thank you Happy holidays :) Mahesh -- patr...@douglas.co.ukDouglas Instruments Ltd. Douglas House, East Garston, Hungerford, Berkshire, RG17 7HD, UK Directors: Peter Baldock, Patrick Shaw Stewart http://www.douglas.co.uk Tel: 44 (0) 148-864-9090US toll-free 1-877-225-2034 Regd. England 2177994, VAT Reg. GB 480 7371 36
[ccp4bb] structural homologs as cross seeds
Also see Acta Cryst. (2013). D69, 1433-1446[ doi:10.1107/S0907444913015126http://dx.doi.org/10.1107/S0907444913015126 ] Best wishes Elspeth From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of Allister Crow Sent: 27 December 2013 21:31 To: CCP4BB@JISCMAIL.AC.UK Subject: Re: [ccp4bb] structural homologs as cross seeds I know of at least one published example where seeding has been used to crystallise a number of homologues: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2243101/ (Sanchez-Weatherby 2006, Acta Cryst F 62:518) There are probably others out there... Certainly worth giving it a go. Best wishes, - Allister On 27 December 2013 19:29, Mahesh Lingaraju mxl1...@psu.edumailto:mxl1...@psu.edu wrote: Dear all, I was wondering if it sounds logical to use the crystals from a possible structural homolog as seeds to induce nucleation ? (in terms of overall sequence, the proteins are considerably different but based on sequence alignment and structures from other related proteins, it is highly likely the protein would have the same structure.) Please comment if any of you had experience with this. Thank you Happy holidays :) Mahesh
Re: [ccp4bb] structural homologs as cross seeds
Thanks for the input folks. Ill surely try it. Hopefully some christmas/new year miracles will happen. Thanks again Mahesh Dear all, I was wondering if it sounds logical to use the crystals from a possible structural homolog as seeds to induce nucleation ? (in terms of overall sequence, the proteins are considerably different but based on sequence alignment and structures from other related proteins, it is highly likely the protein would have the same structure.) Please comment if any of you had experience with this. Thank you Happy holidays :) Mahesh
[ccp4bb] structural homologs as cross seeds
Dear all, I was wondering if it sounds logical to use the crystals from a possible structural homolog as seeds to induce nucleation ? (in terms of overall sequence, the proteins are considerably different but based on sequence alignment and structures from other related proteins, it is highly likely the protein would have the same structure.) Please comment if any of you had experience with this. Thank you Happy holidays :) Mahesh
Re: [ccp4bb] structural homologs as cross seeds
I do not have experience with this but it is worth trying. On Fri, Dec 27, 2013 at 2:29 PM, Mahesh Lingaraju mxl1...@psu.edu wrote: Dear all, I was wondering if it sounds logical to use the crystals from a possible structural homolog as seeds to induce nucleation ? (in terms of overall sequence, the proteins are considerably different but based on sequence alignment and structures from other related proteins, it is highly likely the protein would have the same structure.) Please comment if any of you had experience with this. Thank you Happy holidays :) Mahesh
Re: [ccp4bb] structural homologs as cross seeds
the differences are likely to be on the protein surface, and these would make the crystal contacts, i.e. it would be unlikely the protein could crystallise in the same crystal habit. Never say never in crystallisation (i.e. try anything), but I would go for other things first like additives, different crystallisation techniques, temperatures, concentrations etc. On 27 Dec 2013, at 20:29, Mahesh Lingaraju wrote: Dear all, I was wondering if it sounds logical to use the crystals from a possible structural homolog as seeds to induce nucleation ? (in terms of overall sequence, the proteins are considerably different but based on sequence alignment and structures from other related proteins, it is highly likely the protein would have the same structure.) Please comment if any of you had experience with this. Thank you Happy holidays :) Mahesh
Re: [ccp4bb] structural homologs as cross seeds
I know of at least one published example where seeding has been used to crystallise a number of homologues: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2243101/ (Sanchez-Weatherby 2006, Acta Cryst F 62:518) There are probably others out there... Certainly worth giving it a go. Best wishes, - Allister On 27 December 2013 19:29, Mahesh Lingaraju mxl1...@psu.edu wrote: Dear all, I was wondering if it sounds logical to use the crystals from a possible structural homolog as seeds to induce nucleation ? (in terms of overall sequence, the proteins are considerably different but based on sequence alignment and structures from other related proteins, it is highly likely the protein would have the same structure.) Please comment if any of you had experience with this. Thank you Happy holidays :) Mahesh
