Page 88 - Macromolecular Crystallography

CHAPTER 5

In-house macromolecular data

collection

Mark R. Sanderson

5.1 Introduction
detectors, developed by Charpak to detect high-
In the field of macromolecular crystallography a energy particles in collider experiments (Charpak,
renaissance occurred in data collection with the 1988; Charpak et al., 1968, 1989), for use in single-
advent of two-dimensional area detectors. These crystal X-ray diffraction studies. Xuong, Hamlin,
rapidlysupersededfilmcamerasanddiffractometers Nielsen, Howard, and coworkers developed a
fittedwithproportionalcountersasthetoolsofchoice method of collecting screenless images on these
for macromolecular data collection, resulting in a detectors (Xuong et al., 1985b, Howard et al., 1985;
huge increase in collection speeds.Atypical data col- Edwards et al., 1988). Even though the multiwire
lection to high resolution on a diffractometer would detectors heralded a new era of data collection,
takeamatterofweeksusing, typically, fivetotencap- the older multiwire detectors have now been sur-
illarymountedcrystals.Forthedurationthatacrystal passed by image plate and CCD technology. Having
lastedintheX-raybeamindividualdiffractionreflec- said that, Bruker AXS is developing a new detec-
tions were then collected in resolution shells, with tor based on multiwire technology with a greater
overlap between shells for scaling. The full dataset sensitivity by incorporating a very narrow wire
was then formed by merging and scaling the res- spacing and hence using the superb feature of
olution shells. The first detectors to be introduced these detectors; namely, that they are single pho-
reduced data collection times from weeks to a matter ton counters with high detected quantum efficiency
of days, with the possibility of collecting a full data (DQE) (Schierbeek, 2006). The multiwire detectors
set on a single crystal before it decayed. The advent have been excellently reviewed in Garman (1991)
of cryocooling occurred soon after the introduction and Kahn and Fourme (1997). The FAST system,
of area detectors and this further augmented data incorporating a scintillation screen and a TV scan-
quality through collection effectively without decay. ning system, which was developed by Arndt and
The first detectors to be introduced were two- coworkers at the LMB, Cambridge and commercial-
dimensional Multiwire detectors and the FAST ized by Enraf-Nonius, Delft, was used in a num-
detector. The first multiwire detectors were devel- ber of leading crystallographic laboratories (Arndt,
oped and commercialized by Prof. Nguyen-huu 1985, 1982).
Xuong, Ron Hamlin, and coworkers in San Diego In this Chapter I have focused on in-house data
(San Diego multiwire detector SDMW) (Cork et al., collection, as data collection at synchrotrons is cov-
1975; Xuong et al., 1985a; Hamlin, 1981, 1985) and ered in this volume by Wasserman et al., Chapter 12 .
Ron Burns and coworkers at Harvard (Xentronics Naturally, the techniques and strategy for collecting
detector) (Durban et al., 1986). These groups modi- data in-house and at synchrotrons have a great deal
fied the technology used in two-dimensional particle in common.

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