[ccp4bb] Active site Volume
Hello CCP4bb: Help me to advice any program/server to calculate active site volume without substrate/inhibitor and volume of the substrate/inhibitor itself. Q-site-finder website is not working. Thank you, Ayan
[ccp4bb] a question related to WinCoot 0.8.1
Dear All, When I use WinCoot 0.8.1 to open a PDB file, it comes, Fix Nomenclature Errors. Correct them? Asp [spec: 1 A 128 ]PHE[spec: 1 A 134]PHE [spec: 1 A 371] But when I check the 3 residues, I cannot find any error. Will you let me know the issue? Dialing
[ccp4bb] CCP4 Scalepack2mtz problem: Anisotropy correction failed
Dear All, I tried to convert my x-ray diffraction sca data from HKL200 (.sca file) to mtz in CCP4 using Scalepack2mtz and it failed, I do not know what should I supposed to do next to correct the problem, any suggestions are appreciated. I pasted the message from part of log file below: ANISOTROPY ANALYSIS (using intensities): Eigenvalues: -0.5668 0.1479 0.3584 Eigenvalue ratios: -1.5815 0.4128 1. ctruncate: Anisotropy correction failed - negative eigenvalue. Times: User: 0.4s System: 0.0s Elapsed: 0:00 *** * Information from CCP4Interface script *** The program run with command: /Applications/ccp4-6.4.0/bin/ctruncate -hklin /LAB/CCP4/TEMP/RelADD_12212014ALS502_3_1_mtz.tmp -hklout /LAB/CCP4/TEMP/RelADD_12212014ALS502_3_3_mtz.tmp -colin /*/*/\[IMEAN,SIGIMEAN\] -colout P1_12 has failed with error message ctruncate: Anisotropy correction failed - negative eigenvalue. ObjectCache: Leaked 0005 refs to *** #CCP4I TERMINATION STATUS 0 ctruncate: Anisotropy correction failed - negative eigenvalue. ObjectCache: Leaked 0005 refs to #CCP4I TERMINATION TIME 09 Jan 2015 19:55:50 #CCP4I MESSAGE Task failed
Re: [ccp4bb] active 3D monitors: successor of Asus VG278HR?
Dear Jens, Jim, Todd and all, Thanks for your replies and suggestions! Yes, you are right, if you do not get your hands on a monitor with built-in emitter, you'll need ad least a K4000 That is the reason I was looking for the monitor with built-in emitter, because then I could use the much cheaper K600 (about $ 140) instead. When I compare former prices for the VG278HR (about $ 500) plus K600 card, with the bundle of VG278HE (about $ 370) plus K4000 (about $ 700) plus emitter (included in the kit $ 170), there is a difference of about $ 500. So my question is: Is the K4000 really much better than the K600 for crystallographic purposes? Has anybody used similar cards (both) and can tell if this difference is really significant? Some suggestions are that even integrated graphics chips are fine (at least for coot), see here and follow-up messages https://www.mail-archive.com/ccp4bb@jiscmail.ac.uk/msg34801.html But I guess if I cannot find a monitor with built-in emitter, the K4000 plus VG278HE will be one of my few choices Thanks and best wishes, Tobias. On Fri, Jan 9, 2015 at 6:11 AM, Jens Kaiser kai...@caltech.edu wrote: In addition to what others have -- correctly -- stated I want to add one more thing: Yes, you are right, if you do not get your hands on a monitor with built-in emitter, you'll need ad least a K4000 and in many cases the VESA din bracket (~$50). You do not have to buy the expensive ($800+) 3D Vision pro emitter, though, for about $150 you can get the 3D Vision 2 (the 2 is important!) kit, that includes the DIN-to-Phone jack cable (officially for connection to DLP) you'll need to connect the graphics card to the emitter. Don't use the DP-DVI adapter, there's not enough bandwidth - go straight out of the DVI and you'll be fine (this realization cost me a day). HTH, Jens On Thu, 2015-01-08 at 15:08 +0100, Tobias Beck wrote: Dear all, I am looking again at 3D monitors. Last year I bought for my old lab the VG278HR and the PNY K600, as advised by the CCP4BB. (The 3D test images from Nvidia were running fine under Windows, but I did not get around to finish the set up with pymol and coot under linux.) Now at a new place, I looked at available monitors again (that have the built-in emitter since I want to use the K600 graphics card) and noticed that the VG278HR is out of stock. The VG278H, which seems to be a very similar model, is also out of stock. This page http://www.nvidia.com/object/3d-vision-displays.html also lists the Acer HN274H as a 27'' monitor with built-in emitter, but that seems to be out of stock as well (I would prefer not to buy a refurbished or used one). The monitors mentioned above are also listed here: http://strucbio.biologie.uni-konstanz.de/ccp4wiki/index.php/Stereo (The smaller BenQ XL2420TX listed there is also out of stock). Has anybody ordered a 3D monitor with built-in emitter recently or could provide me with a current list of 27'' monitors with built-in emitters? I checked with Nvidia via their chat support, but they did not have an updated list, just provided links to the manufacturers' homepages. If monitors with built-in emitters are not available anymore, I need to buy a different graphics card in order for the setup to work with linux, right? Thank you and best wishes, Tobias. -- ___ Dr. Tobias Beck - group leader - RWTH Aachen University Institute of Inorganic Chemistry Landoltweg 1, office: 304N 52056 Aachen, Germany phone: +49-241-80-90057 fax: +49-241-80-99003 ___ -- ___ Dr. Tobias Beck - independent group leader - RWTH Aachen University Institute of Inorganic Chemistry Landoltweg 1, office: 304N 52056 Aachen, Germany phone: +49-241-80-90057 fax: +49-241-80-99003 web: http://www.ac.rwth-aachen.de/extern/beck/ ___
Re: [ccp4bb] active 3D monitors: successor of Asus VG278HR?
Dear Tobias, BenQ (Model: XL2411Z - 24W 3D monitor) ViewSonic (VX2268wm - 22 3D monitor) NVIDIA 3D Vision 2 Kit 1. Both the abovementioned monitors work well on Linux/Ubuntu with the NVIDIA Quadro K4000 graphics card. You may have to edit the Xorg file for proper 3D access in BenQ or ViewSonic accordingly. However, as others mentioned, you need 3pin-mini-DIN slot to work on Linux/Ubuntu. 2. In one of our other PC has MS Windows 7 ( and Ubuntu is under Virtual Box) - NVIDIA Quadro K600 works well. We use Windows OS for 3D (such as for Coot), and Ubuntu (virtual machine) for crystallography calculations (say, CCP4). Regards, Paddy. * B. Padmanabhan, Ph. D Additional Professor Department of Biophysics NIMHANS Bangalore - 560029 India. On Fri, Jan 9, 2015 at 1:48 PM, Tobias Beck tobiasb...@gmail.com wrote: Dear Jens, Jim, Todd and all, Thanks for your replies and suggestions! Yes, you are right, if you do not get your hands on a monitor with built-in emitter, you'll need ad least a K4000 That is the reason I was looking for the monitor with built-in emitter, because then I could use the much cheaper K600 (about $ 140) instead. When I compare former prices for the VG278HR (about $ 500) plus K600 card, with the bundle of VG278HE (about $ 370) plus K4000 (about $ 700) plus emitter (included in the kit $ 170), there is a difference of about $ 500. So my question is: Is the K4000 really much better than the K600 for crystallographic purposes? Has anybody used similar cards (both) and can tell if this difference is really significant? Some suggestions are that even integrated graphics chips are fine (at least for coot), see here and follow-up messages https://www.mail-archive.com/ccp4bb@jiscmail.ac.uk/msg34801.html But I guess if I cannot find a monitor with built-in emitter, the K4000 plus VG278HE will be one of my few choices Thanks and best wishes, Tobias. On Fri, Jan 9, 2015 at 6:11 AM, Jens Kaiser kai...@caltech.edu wrote: In addition to what others have -- correctly -- stated I want to add one more thing: Yes, you are right, if you do not get your hands on a monitor with built-in emitter, you'll need ad least a K4000 and in many cases the VESA din bracket (~$50). You do not have to buy the expensive ($800+) 3D Vision pro emitter, though, for about $150 you can get the 3D Vision 2 (the 2 is important!) kit, that includes the DIN-to-Phone jack cable (officially for connection to DLP) you'll need to connect the graphics card to the emitter. Don't use the DP-DVI adapter, there's not enough bandwidth - go straight out of the DVI and you'll be fine (this realization cost me a day). HTH, Jens On Thu, 2015-01-08 at 15:08 +0100, Tobias Beck wrote: Dear all, I am looking again at 3D monitors. Last year I bought for my old lab the VG278HR and the PNY K600, as advised by the CCP4BB. (The 3D test images from Nvidia were running fine under Windows, but I did not get around to finish the set up with pymol and coot under linux.) Now at a new place, I looked at available monitors again (that have the built-in emitter since I want to use the K600 graphics card) and noticed that the VG278HR is out of stock. The VG278H, which seems to be a very similar model, is also out of stock. This page http://www.nvidia.com/object/3d-vision-displays.html also lists the Acer HN274H as a 27'' monitor with built-in emitter, but that seems to be out of stock as well (I would prefer not to buy a refurbished or used one). The monitors mentioned above are also listed here: http://strucbio.biologie.uni-konstanz.de/ccp4wiki/index.php/Stereo (The smaller BenQ XL2420TX listed there is also out of stock). Has anybody ordered a 3D monitor with built-in emitter recently or could provide me with a current list of 27'' monitors with built-in emitters? I checked with Nvidia via their chat support, but they did not have an updated list, just provided links to the manufacturers' homepages. If monitors with built-in emitters are not available anymore, I need to buy a different graphics card in order for the setup to work with linux, right? Thank you and best wishes, Tobias. -- ___ Dr. Tobias Beck - group leader - RWTH Aachen University Institute of Inorganic Chemistry Landoltweg 1, office: 304N 52056 Aachen, Germany phone: +49-241-80-90057 fax: +49-241-80-99003 ___ -- ___ Dr. Tobias Beck - independent group leader - RWTH Aachen University Institute of Inorganic Chemistry Landoltweg 1, office: 304N 52056 Aachen, Germany phone: +49-241-80-90057 fax: +49-241-80-99003 web: http://www.ac.rwth-aachen.de/extern/beck/ ___
Re: [ccp4bb] Protein precipitating at higher concentration!!
Hi Ivan, according to my experience, if you remove at the same time GuHCl and Triton, you have huge risk of precipitation if the protein is not properly folded. In my opinion, you have to do something like re-folding. It seems that your protein could be solubilized from inclusion-body. In the same case, the first thing that i will do : I start with the same protocol as you do, but after the TALON, i will dialysis gently the sample against the same buffer without the GuHCL but with Triton. Maybe you ca try to change the pH. Tris-HCl is a good strating point, but maybe you a to refine this. Phosphate buffer (7.5) helped me sometimes. What is the Pi of your protein ? Hope to help you. Nicolas De : CCP4 bulletin board [CCP4BB@JISCMAIL.AC.UK] de la part de CHAVAS Leonard [ccp4hnaa...@gmail.com] Envoyé : vendredi 9 janvier 2015 01:41 À : CCP4BB@JISCMAIL.AC.UK Objet : Re: [ccp4bb] Protein precipitating at higher concentration!! Hi Ivan this will not be an answer to your question, but did you consider not concentrating 'too much' your sample? It happened few times to me that the protein was precipitating when concentrating for SEC because of the presence of other impurities. Trying the good old AS precipitation helped a bit, but wasn't really the magical solution as I was losing a bit of the protein of interest as well. The solution was to concentrate only slightly the sample, and pass it though multiple (at the time it was quite a lot actually) runs of SEC. I ended up with again a lot of pure sample to concentrate, however, this sample was pure enough and did not precipitate. Other than that, I guess playing with the salt concentration might help keeping things stable... or not. I know people also tried the addition of glycerol or EG, but I don't have personal experience in that and cannot really comment if it is working well or not. Cheers, Leo On Jan 9, 2015, at 9:00 AM, xaravich ivan xaravich.i...@gmail.com wrote: Hi Xtallographers, I have been able to purify a protein that was initially going into inclusion bodies from the excellent suggestions that I got here. So my lysis buffer has 0.5M Guanidium Hydrochoride, 2% TritonX-100, 500mM NaCl, 5% Glycerol in 20 mM Tris-HCL pH 8.0 The problem is that the protein is first purified as a SUMO-fusion protein which is further proteolysed and passed through the Talon resin to get the final SUMO-Free construct. However as I have around 250mM Imidazole (pH elution did not work) from the elution of the first round, I have to dialyse the sample to get rid of the imidazole so that I can use the proteolysed sample again on the column. All these I do in a buffer that does not have GuHCL or Triton. However I have kept the NaCl concentration same (0.5 M). I start to see white insoluble precipitate right from the dialysis step. If I spin the precipitate out, I still have a lot of protein to go to the next step of proteolysis. The problem is that when I finally want to concentrate the protein to run the SEC step, all my protein starts precipitating starting from 5mg/ml to all the way to 25-30 mg/ml. Are there some smart ways to keep the protein soluble at higher concentrations, assuming that I do not have to remove them before setting up trays? Should I keep on using Guanidium Hcl and Triton for all the steps all the way into the SEC column. Have people got any good results using 5% Acetronitrile, 50mM Arginine or DTT? (used for NMR samples) Any help in this regard will be very helpful. The protein is an engineered bacterial transcription factor. (not a membrane protein) Thanks in advance as always, ivan
Re: [ccp4bb] Off-topic - PyMol map sampling at unit cell boundary
On 09/01/15 21:08, Shane Caldwell wrote: Hi ccp4bb, Apologies for a cross-post. I previously asked this question on the pymol-users mailing list, but I thought I'd ask here as well, in case someone who doesn't follow that bb might have run into my problem rendering maps in PyMol. I'm starting to think it's a non-trival problem to solve. I'm drawing a mesh based on a ccp4 map exported from coot. To get finer sampling, I use the map_double command (twice sequentially, but the problem is visible after the first). Doubling the map introduces a discontinuity. The second doubling introduces a gap, but even even the first has a visible distortion. (see linked images below) This discontinuity lines up with the unit cell boundary, so it has something to do with sampling at the unit cell edge (the cell boundary is faintly visible in the background of the linked images). Not sure if there's a simple fix I'm overlooking or if it's a fundamental limitation of the sampling algorithm. Any help you can provide would be great! I've linked images of the same map at all 3 samplings below: Parent map: http://imgur.com/i46YH6r Doubled once: http://imgur.com/Vy8oJfx Doubled twice: http://imgur.com/q3gO0cI That's amusing. Looks like a pymol bug (but of course, given the source of this comment, you should take that with a pinch of salt). As a work-around, I'd advise that you turn up the map sampling rate to 2.8 or so in Coot (before you read in your mtz file and subsequently export the map (fragment)) - then you won't need pymol map doubling. Paul.
Re: [ccp4bb] Bulk solvent
Dear Armando, Is there any reason for using Babinet scaling for bulk solvent correction instead of mask based scaling? in addition to Dirk's excellent comment: Babinet bulk-solvent model is fine at resolutions lower than 15-20Å while not so much at higher resolutions as demonstrated by Podjarny, A. D. Urzhumtsev, A.G. (1997). Methods Enzymol. 276,641-658). Pavel
[ccp4bb] Off-topic - PyMol map sampling at unit cell boundary
Hi ccp4bb, Apologies for a cross-post. I previously asked this question on the pymol-users mailing list, but I thought I'd ask here as well, in case someone who doesn't follow that bb might have run into my problem rendering maps in PyMol. I'm starting to think it's a non-trival problem to solve. I'm drawing a mesh based on a ccp4 map exported from coot. To get finer sampling, I use the map_double command (twice sequentially, but the problem is visible after the first). Doubling the map introduces a discontinuity. The second doubling introduces a gap, but even even the first has a visible distortion. (see linked images below) This discontinuity lines up with the unit cell boundary, so it has something to do with sampling at the unit cell edge (the cell boundary is faintly visible in the background of the linked images). Not sure if there's a simple fix I'm overlooking or if it's a fundamental limitation of the sampling algorithm. Any help you can provide would be great! I've linked images of the same map at all 3 samplings below: Parent map: http://imgur.com/i46YH6r Doubled once: http://imgur.com/Vy8oJfx Doubled twice: http://imgur.com/q3gO0cI Thanks for your indulgence! Shane Caldwell McGill University
Re: [ccp4bb] Bulk solvent
On 09.01.2015 08:56, Armando Albert wrote: Dear all, Is there any reason for using Babinet scaling for bulk solvent correction instead of mask based scaling? Armando Dear Armando, yes: the mask bulk solvent correction depends on the proper calculation of a protein mask. The bulk solvent density is then assigned outside the protein mask. This mask calculation is based on one or two radii around the protein atoms and is always a compromise. Sometimes, the protein mask misses really empty cavities usually surrounded by hydrophobic residues, wrongly filling these cavities with bulk solvent density. This results in relatively large blobs with negative difference density. Sometimes, the protein mask covers narrow cavities really filled with bulk solvent electron density, which is then missing in the model. This results in positive difference densities, that are not easy to interpret. The Babinet bulk solvent correction only uses two parameters, is less effective in describing the contribution of the bulk solvent to the scattering, but is free of these artefacts. I use the Babinet bulk solvent correction sometimes as a control if I'm not sure about the origin of possibly important difference density peaks in narrow regions. Best regards, Dirk. -- *** Dirk Kostrewa Gene Center Munich, A5.07 Department of Biochemistry Ludwig-Maximilians-Universität München Feodor-Lynen-Str. 25 D-81377 Munich Germany Phone: +49-89-2180-76845 Fax:+49-89-2180-76999 E-mail: kostr...@genzentrum.lmu.de WWW:www.genzentrum.lmu.de ***
Re: [ccp4bb] imosflm error
Hi, I suggest you upgrade to ccp4-6.5 in the first place. I used to have this problem (or a similar one) with the initial 6.4 release but it has been fixed with later updates. In 6.5 it's completely gone (I'm using Centos 6.6) Cheers, Boaz Boaz Shaanan, Ph.D. Dept. of Life Sciences Ben-Gurion University of the Negev Beer-Sheva 84105 Israel E-mail: bshaa...@bgu.ac.il Phone: 972-8-647-2220Skype: boaz.shaanan Fax: 972-8-647-2992 or 972-8-646-1710 From: CCP4 bulletin board [CCP4BB@JISCMAIL.AC.UK] on behalf of Pooja Kesari [pkesar...@gmail.com] Sent: Friday, January 09, 2015 3:31 PM To: CCP4BB@JISCMAIL.AC.UK Subject: [ccp4bb] imosflm error Dear All, Whenever I start imosflm there was an error message iMosflm version 7.1.1, 24th March 2014ipmosflm is not compatible.Please configure iMosflm with the correct executable.on configure the imosflm window is closed and there Tcl platform is unix x86_64 Linux 2.6.32-431.23.3.el6.x86_64 TclTk version from info patchlevel is 8.4.19 Tk windowing system is x11 Error in startup script: invalid command name while executing $::session setMultipleImageFiles 0 while constructing object ::.mosflmExecutable in ::Fileopen::constructor (body line 145) invoked from within Fileopen .mosflmExecutable -type open -initialdir [pwd] -filtertypes {{All Files {.*}}} (object ::.c method ::Controller::initialize body line 115) invoked from within .c initialize (file /home/programs/ccp4-6.4.0/share/ccp4i/imosflm/src/imosflm.tcl line 472) invoked from within source $env(IMOSFLM) (file /home/programs/ccp4-6.4.0/share/ccp4i/imosflm/imosflm.tcl line 159) MOSDIR is /home/user1/projects/lpxa_all/ccp4ill, Whenever I start imosflm from the data processing and analysis using Mosflm. there was an error message iMosflm version 7.1.1, 24th March 2014ipmosflm is not compatible.Please configure iMosflm with the correct executable.on configure the imosflm window is closed and there Tcl platform is unix x86_64 Linux 2.6.32-431.23.3.el6.x86_64 TclTk version from info patchlevel is 8.4.19 Tk windowing system is x11 Error in startup script: invalid command name while executing $::session setMultipleImageFiles 0 while constructing object ::.mosflmExecutable in ::Fileopen::constructor (body line 145) invoked from within Fileopen .mosflmExecutable -type open -initialdir [pwd] -filtertypes {{All Files {.*}}} (object ::.c method ::Controller::initialize body line 115) invoked from within .c initialize (file /home/programs/ccp4-6.4.0/share/ccp4i/imosflm/src/imosflm.tcl line 472) invoked from within source $env(IMOSFLM) (file /home/programs/ccp4-6.4.0/share/ccp4i/imosflm/imosflm.tcl line 159) MOSDIR is /home/user1/projects/lpxa_all/ccp4i please help!!! -- Thanks Regards, Pooja Kesari Research Scholar Department Of Biotechnology Indian Institute of Technology Roorkee INDIA
[ccp4bb] imosflm error
Dear All, Whenever I start imosflm there was an error message *iMosflm version 7.1.1, 24th March 2014ipmosflm is not compatible.Please configure iMosflm with the correct executable.on configure* the imosflm window is closed and there *Tcl platform is unix x86_64 Linux 2.6.32-431.23.3.el6.x86_64TclTk version from info patchlevel is 8.4.19Tk windowing system is x11Error in startup script: invalid command name while executing$::session setMultipleImageFiles 0while constructing object ::.mosflmExecutable in ::Fileopen::constructor (body line 145)invoked from withinFileopen .mosflmExecutable -type open -initialdir [pwd] -filtertypes {{All Files {.*}}}(object ::.c method ::Controller::initialize body line 115)invoked from within.c initialize(file /home/programs/ccp4-6.4.0/share/ccp4i/imosflm/src/imosflm.tcl line 472)invoked from withinsource $env(IMOSFLM)(file /home/programs/ccp4-6.4.0/share/ccp4i/imosflm/imosflm.tcl line 159) MOSDIR is /home/user1/projects/lpxa_all/ccp4ill,Whenever I start imosflm from the data processing and analysis using Mosflm.there was an error message iMosflm version 7.1.1, 24th March 2014ipmosflm is not compatible.Please configure iMosflm with the correct executable.on configurethe imosflm window is closed and there Tcl platform is unix x86_64 Linux 2.6.32-431.23.3.el6.x86_64TclTk version from info patchlevel is 8.4.19Tk windowing system is x11Error in startup script: invalid command name while executing$::session setMultipleImageFiles 0while constructing object ::.mosflmExecutable in ::Fileopen::constructor (body line 145)invoked from withinFileopen .mosflmExecutable -type open -initialdir [pwd] -filtertypes {{All Files {.*}}}(object ::.c method ::Controller::initialize body line 115)invoked from within.c initialize(file /home/programs/ccp4-6.4.0/share/ccp4i/imosflm/src/imosflm.tcl line 472)invoked from within* *source $env(IMOSFLM)(file /home/programs/ccp4-6.4.0/share/ccp4i/imosflm/imosflm.tcl line 159) MOSDIR is /home/user1/projects/lpxa_all/ccp4i* please help!!! -- Thanks Regards, Pooja Kesari Research Scholar Department Of Biotechnology Indian Institute of Technology Roorkee INDIA
Re: [ccp4bb] active 3D monitors: successor of Asus VG278HR?
On 01/09/2015 12:11 AM, Jens Kaiser wrote: In addition to what others have -- correctly -- stated I want to add one more thing: Yes, you are right, if you do not get your hands on a monitor with built-in emitter, you'll need ad least a K4000 and in many cases the VESA din bracket (~$50). You do not have to buy the expensive ($800+) 3D Vision pro emitter, though, for about $150 you can get the 3D Vision 2 (the 2 is important!) kit, that includes the DIN-to-Phone jack cable (officially for connection to DLP) you'll need to connect the graphics card to the emitter. Don't use the DP-DVI adapter, there's not enough bandwidth - go straight out of the DVI and you'll be fine (this realization cost me a day). This is getting rather distant from the central topic, but here is clarification on a couple points mentioned above: 1) 3D Vision Pro uses a wireless signal to communicate between the emitter and the glasses. It costs more. The glasses must also be Pro compatible, and the intended purpose is for a roomful of viewers at a time. 3D Vision 2 is probably what you want; it uses infrared to communicate between the emitter and the glasses. Line of sight is necessary. NVidia 3D Vision 2 Wireless Glasses Kit includes emitter, one pair of glasses, cables and accessories. Model number is 942-11431-0007-001 Extra 3D Vision 2 glasses: model number 942-11431-0003-001 2) DP as mentioned above is Displayport. The issue you had with the DP-DVI adapter is probably that you were dealing with a Displayport to single link DVI adapter. It is the single link DVI, not the Displayport that does not have adequate bandwidth for a 1920x1080x120Hz display. The same problem would probably occur if you used the DVI port with a single link DVI cable. I would expect a stereo-ready monitor to come with a dual link DVI cable. DP-dual link DVI adapters are available, if you look hard enough. You can distinguish between single link and dual link DVI by the number of pins; see Wikipedia for details. --- Current specifications for Displayport (1.2+) and HDMI(2.0+) have enough bandwidth for 1920x1080x120Hz, but there don't seem to be any Displayport stereo monitors on the market. I would guess this is due to a lack of consumer demand, with 3D television and gaming not having caught on. The introduction of organic LED (OLED) screens, which is expected in the next few years, should also benefit stereo technology, but once again we are at the mercy of the gaming market. 3D headsets (e.g. Oculus Rift) are due for introduction in the next year or so, which should be fine for one person but not so much for sharing. Cheers, -- === All Things Serve the Beam === David J. Schuller modern man in a post-modern world MacCHESS, Cornell University schul...@cornell.edu