A, yes, inventor's names. Anyone reading who is less than 40 and knows what MTZ stands for?
;-) My favorite technique remains SADDAM - a side product of Gerard's War On Error, that never did catch-up with the masses - experimentally or as an acronym. A. On 19 Jan 2012, at 21:51, Petr Leiman wrote: > It would be so much more convenient to call these techniques (MAD, SAD, etc.) > by their inventor's name. This would simplify things immensely simultaneously > eliminating CCP4BB MADisagreements. > > Although in our days of copyrights wars, the journals and perhaps conferences > where these methods were presented for the first time would insist on using > their names as part of the method's name... > > Petr > > > On Jan 19, 2012, at 7:42 PM, Ethan Merritt wrote: > >> On Thursday, 19 January 2012, Ian Tickle wrote: >>> So what does this have to do with the MAD acronym? I think it stemmed >>> from a visit by Wayne Hendrickson to Birkbeck in London some time >>> around 1990: he was invited by Tom Blundell to give a lecture on his >>> MAD experiments. At that time Wayne called it multi-wavelength >>> anomalous dispersion. Tom pointed out that this was really a misnomer >>> for the reasons I've elucidated above. Wayne liked the MAD acronym >>> and wanted to keep it so he needed a replacement term starting with D >>> and diffraction was the obvious choice, and if you look at the >>> literature from then on Wayne at least consistently called it >>> multi-wavelength anomalous diffraction. >> >> Ian: >> >> The change-over from "dispersion" to "diffraction" in MAD protein >> crystallography happened a couple of years earlier, at least with regard >> to work being done at SSRL. I think the last paper using the term >> "dispersion" was the 1988 Lamprey hemoglobin paper. The next two papers, >> one a collaboration with Wayne's group and the other a collaboration >> with Hans Freeman's group, used the term "diffraction". >> >> WA Hendrickson, JL Smith, RP Phizackerley, EA Merritt. >> Crystallographic structure-analysis of lamprey hemoglobin from >> anomalous dispersion of synchrotron radiation. >> PROTEINS-STRUCTURE FUNCTION AND GENETICS, 4(2):77–88, 1988. >> >> JM Guss, EA Merritt, RP Phizackerley, B Hedman, M Murata, >> KO Hodgson, HC Freeman. >> Phase determination by multiple-wavelength X-ray-diffraction - >> crystal-structure of a basic blue copper protein from cucumbers. >> SCIENCE, 241(4867):806–811, AUG 12 1988. >> >> WA Hendrickson, A Pahler, JL Smith, Y Satow, EA Merritt, RP Phizackerley. >> Crystal structure of core streptavidin determined from multiwavelength >> anomalous diffraction of synchrotron radiation. >> PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF >> AMERICA, 86(7):2190–2194, APR 1989. >> >> On the other hand, David and Lilo Templeton continued to use the term >> "anomalous dispersion" for at least another decade, describing their >> diffraction experiments exploring polarization effects and other >> characteristics of near-edge X-ray scattering by elements all over the >> periodic table. >> >> Ethan >> >> >>> Cheers >>> >>> -- Ian >>> >>> On 18 January 2012 18:23, Phil Jeffrey <pjeff...@princeton.edu> wrote: >>>> Can I be dogmatic about this ? >>>> >>>> Multiwavelength anomalous diffraction from Hendrickson (1991) Science Vol. >>>> 254 no. 5028 pp. 51-58 >>>> >>>> Multiwavelength anomalous diffraction (MAD) from the CCP4 proceedings >>>> http://www.ccp4.ac.uk/courses/proceedings/1997/j_smith/main.html >>>> >>>> Multi-wavelength anomalous-diffraction (MAD) from Terwilliger Acta Cryst. >>>> (1994). D50, 11-16 >>>> >>>> etc. >>>> >>>> >>>> I don't see where the problem lies: >>>> >>>> a SAD experiment is a single wavelength experiment where you are using the >>>> anomalous/dispersive signals for phasing >>>> >>>> a MAD experiment is a multiple wavelength version of SAD. Hopefully one >>>> picks an appropriate range of wavelengths for whatever complex case one >>>> has. >>>> >>>> One can have SAD and MAD datasets that exploit anomalous/dispersive signals >>>> from multiple difference sources. This after all is one of the things that >>>> SHARP is particularly good at accommodating. >>>> >>>> If you're not using the anomalous/dispersive signals for phasing, you're >>>> collecting native data. After all C,N,O,S etc all have a small anomalous >>>> signal at all wavelengths, and metalloproteins usually have even larger >>>> signals so the mere presence of a theoretical d" difference does not make >>>> it >>>> a SAD dataset. ALL datasets contain some anomalous/dispersive signals, >>>> most >>>> of the time way down in the noise. >>>> >>>> Phil Jeffrey >>>> Princeton >>>> >>>> >>>> >>>> On 1/18/12 12:48 PM, Francis E Reyes wrote: >>>>> >>>>> >>>>> Using the terms 'MAD' and 'SAD' have always been confusing to me when >>>>> considering more complex phasing cases. What happens if you have >>>>> intrinsic >>>>> Zn's, collect a 3wvl experiment and then derivatize it with SeMet or a >>>>> heavy >>>>> atom? Or the MAD+native scenario (SHARP) ? >>>>> >>>>> Instead of using MAD/SAD nomenclature I favor explicitly stating whether >>>>> dispersive/anomalous/isomorphous differences (and what heavy atoms for >>>>> each >>>>> ) were used in phasing. Aren't analyzing the differences (independent of >>>>> source) the important bit anyway? >>>>> >>>>> >>>>> F >>>>> >>>>> >>>>> --------------------------------------------- >>>>> Francis E. Reyes M.Sc. >>>>> 215 UCB >>>>> University of Colorado at Boulder >>>
