Re: [ccp4bb] Sub-angstrom resolution

2012-01-11 Thread Colin Nave
edge leads to average spot intensities being reduced by a factor of 8. Thanks! Colin -Original Message- From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of Dirk Kostrewa Sent: 11 January 2012 09:15 To: ccp4bb Subject: Re: [ccp4bb] Sub-angstrom resolution Dear

Re: [ccp4bb] Sub-angstrom resolution

2012-01-11 Thread Thomas Womack
On 11 Jan 2012, at 11:36, Thomas Womack wrote: > > On 11 Jan 2012, at 02:13, Artem Evdokimov wrote: > >> There are two sides to this qustion: the scientific one is actually easier >> to answer in generic terms - but I also would like to point out the very >> recent example of a mystery that re

Re: [ccp4bb] Sub-angstrom resolution

2012-01-11 Thread Thomas Womack
On 11 Jan 2012, at 02:13, Artem Evdokimov wrote: > There are two sides to this qustion: the scientific one is actually easier to > answer in generic terms - but I also would like to point out the very recent > example of a mystery that required very high resoluton (and orthogonal > techniques)

Re: [ccp4bb] Sub-angstrom resolution

2012-01-11 Thread Dirk Kostrewa
Dear Colin, Am 10.01.12 18:08, schrieb Colin Nave: 3. The structure factors are lower for large unit cells. This will mean they will be harder to detect, particularly if there is a high background. But aren't the total structure factors of a unit cell the sum of the atomic structure fact

Re: [ccp4bb] Sub-angstrom resolution

2012-01-10 Thread Artem Evdokimov
There are two sides to this qustion: the scientific one is actually easier to answer in generic terms - but I also would like to point out the very recent example of a mystery that required very high resoluton (and orthogonal techniques) to answer, namely the puzzle of the light atom in the center

Re: [ccp4bb] Sub-angstrom resolution

2012-01-10 Thread Pavel Afonine
One more to add to Ed's list: highly accurate ultra-high resolution structures may allow calculation of electrostatic potential around protein ligand binding site. There are plenty of reference... Pavel On Tue, Jan 10, 2012 at 11:04 AM, Ed Pozharski wrote: > On Tue, 2012-01-10 at 18:30 +, T

Re: [ccp4bb] Sub-angstrom resolution

2012-01-10 Thread Ed Pozharski
On Tue, 2012-01-10 at 18:30 +, Theresa H. Hsu wrote: > Thank you for the interesting replies so far. > > Please let me ask a related question - at what resolution should we stop > efforts to get better diffracting crystals? Are there *biological* questions > that a model with 1.8-2.0 A resol

Re: [ccp4bb] Sub-angstrom resolution

2012-01-10 Thread Theresa H. Hsu
Thank you for the interesting replies so far. Please let me ask a related question - at what resolution should we stop efforts to get better diffracting crystals? Are there *biological* questions that a model with 1.8-2.0 A resolution (with combination of complementary methods like spectroscopy

Re: [ccp4bb] Sub-angstrom resolution

2012-01-10 Thread Colin Nave
Colin -Original Message- From: Ed Pozharski [mailto:epozh...@umaryland.edu] Sent: 10 January 2012 16:09 To: Nave, Colin (DLSLtd,RAL,DIA) Cc: ccp4bb Subject: Re: [ccp4bb] Sub-angstrom resolution On Tue, 2012-01-10 at 09:04 +, Colin Nave wrote: > Yes, I think Ed's analysis is a bit m

Re: [ccp4bb] Sub-angstrom resolution

2012-01-10 Thread Jacob Keller
I think once you start getting down to such small crystals, the spots are not really important, as the pattern starts getting continuous. Interestingly enough, I guess for single-molecule diffraction, resolution is limited only by radiation damage, and not by any sort of lattice disorder (or even b

Re: [ccp4bb] Sub-angstrom resolution

2012-01-10 Thread Ed Pozharski
On Tue, 2012-01-10 at 09:04 +, Colin Nave wrote: > Yes, I think Ed's analysis is a bit misleading. I apologize if I misled anyone. Re-reading my post, I can see that it lacked precision. Indeed, in a perfect monocrystal all the molecules are lined up perfectly, so I should have emphasized ra

Re: [ccp4bb] Sub-angstrom resolution

2012-01-10 Thread Colin Nave
sage- From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of Ethan Merritt Sent: 09 January 2012 19:47 To: ccp4bb Subject: Re: [ccp4bb] Sub-angstrom resolution On Monday, January 09, 2012 11:37:23 am Ed Pozharski wrote: > On Mon, 2012-01-09 at 18:15 +, Theresa H. Hsu wrote: >

Re: [ccp4bb] Sub-angstrom resolution

2012-01-09 Thread Ethan Merritt
On Monday, January 09, 2012 11:37:23 am Ed Pozharski wrote: > On Mon, 2012-01-09 at 18:15 +, Theresa H. Hsu wrote: > > Dear crystallographers > > > > A theoretical question - can sub-angstrom resolution structures only be > > obtained for a limited set of proteins? Is it impossible to achieve

Re: [ccp4bb] Sub-angstrom resolution

2012-01-09 Thread Ed Pozharski
On Mon, 2012-01-09 at 18:15 +, Theresa H. Hsu wrote: > Dear crystallographers > > A theoretical question - can sub-angstrom resolution structures only be > obtained for a limited set of proteins? Is it impossible to achieve for > membrane proteins and large complexes? > > Theresa On the ma

Re: [ccp4bb] Sub-angstrom resolution

2012-01-09 Thread Jacob Keller
The word "theory" in this thread/question has to be clarified better. Jacob On Mon, Jan 9, 2012 at 1:27 PM, Tim Gruene wrote: > -BEGIN PGP SIGNED MESSAGE- > Hash: SHA1 > > Hi, > > in my opinion the resolution limit of crystals from large complexes/ > membrane proteins is more likely due

Re: [ccp4bb] Sub-angstrom resolution

2012-01-09 Thread Tim Gruene
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Hi, in my opinion the resolution limit of crystals from large complexes/ membrane proteins is more likely due to lattice imperfections and long-range disorder, and cold neither cold temperatures nor stronger radiation sources would circumvent this pro

Re: [ccp4bb] Sub-angstrom resolution

2012-01-09 Thread Cale Dakwar
In theory, no: sub-angstrom resolution can be obtained for any and all proteins, including membrane proteins, and for large complexes. In reality, it becomes technically very difficult to achieve; you would need ever-colder temperatures and ever-stronger irradiation sources. P.S. In theory, the

[ccp4bb] Sub-angstrom resolution

2012-01-09 Thread Theresa H. Hsu
Dear crystallographers A theoretical question - can sub-angstrom resolution structures only be obtained for a limited set of proteins? Is it impossible to achieve for membrane proteins and large complexes? Theresa