yes, but irrespective of how much one knows or thinks one knows, one should avoid being gratuitously offensive. cheers jon
Von: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] Im Auftrag von Ian Tickle Gesendet: Montag, 10. September 2018 12:58 An: CCP4BB@JISCMAIL.AC.UK Betreff: Re: [ccp4bb] Electron density maps for Cryo-EM structures. Hi Marin I was about to comment on that too but then I realised that Pavel is referring to the map _contours_ (which is what most people using a map visualisation program like Coot actually see). So the contoured map does represent an iso-potential surface. I'm sure Pavel is aware that the original cryo-EM maps are 3-dimensional objects. Cheers -- Ian On Mon, 10 Sep 2018 at 10:49, Marin van Heel <0000057a89ab08a1-dmarc-requ...@jiscmail.ac.uk<mailto:0000057a89ab08a1-dmarc-requ...@jiscmail.ac.uk>> wrote: Unfortunately, The problem here lies primarily in the answer given, not so much in the question asked by a newcomer: "1) In cryo-EM maps are not electron density maps but surfaces representing electric potential. " The answer appears to reflect the widespread misunderstanding that EM images (and hence cryo-EM maps) only show the surfaces not the internal density of the complexes we study. In my Imperial College/Leiden University lecture notes, I have always used the below slide to illustrate this point. Cheers, Marin [cid:part1.5DA80E33.F02E5B7D@googlemail.com] On 10/09/2018 01:38, Pavel Afonine wrote: Hi, Is there any sever available to create electron density maps for cryo-em structures? The questions are nonsensical. Here is why: 1) In cryo-EM maps are not electron density maps but surfaces representing electric potential. 2) Creating such a map is essentially carrying on from cryo-EM experiment and obtaining the 3D reconstruction. Are you really sure about what you are asking for? Or, we should create the maps from mmCIF. mmCIF is a file format. It may contain representations of rabbits, boysenberries or some diffraction data. So.. how you think it may be related to cryo-EM, in your particular case? I am particularly interested in those cryo-em structures with high resolution, like 2.6~2.8A. Sure, all are excited about high-res cryo-EM!!! Please give me an education. Sure. One of available universities can do this. Cheers, Pavel ________________________________ To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1 -- ============================================================== Prof Dr Ir Marin van Heel Laboratório Nacional de Nanotecnologia - LNNano CNPEM/LNNano, Campinas, Brazil Skype: Marin.van.Heel email: marin.vanheel(A_T)gmail.com<http://gmail.com> marin.vanheel(A_T)lnnano.cnpem.br<http://lnnano.cnpem.br> and: mvh.office(A_T)gmail.com<http://gmail.com> -------------------------------------------------- Emeritus Professor of Cryo-EM Data Processing Leiden University -------------------------------------------------- Emeritus Professor of Structural Biology Imperial College London Faculty of Natural Sciences email: m.vanheel(A_T)imperial.ac.uk<http://imperial.ac.uk> -------------------------------------------------- I receive many emails per day and, although I try, there is no guarantee that I will actually read each incoming email. ________________________________ To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1 ________________________________ To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1 ######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1
