Electron density maps of lysozyme calculated using synchrotron laue data comprising singles and deconvoluted multiples

We have used lysozyme as a test case to illustrate the application of a new method of estimating the intensities of Laue multiples reflection data in protein crystallography. Hen egg-white lysozyme, an enzyme with a single polypeptide chain of 129 amino acids, crystallizes in space group P43212 with cell parametersa=b=79·1 Å,c=37·9 Å. Laue image plate data were collected using synchrotron radiation on station 9·5 at Daresbury with a total exposure time of 0·95 seconds. The data processed were separated into two data sets comprising the singles and the combined singles and deconvoluted multiples. The method of deconvolution was that of Campbell and Hao (1993), which utilizes the intensity variation of theλ-curve. Electron density maps (2Fo−Fc) based on the two data sets are then compared. This comparison shows that the deconvoluted multiples do indeed contribute usefully to the continuity of the maps due to the improved completeness of the data. A number of map sections along the polypeptide chain, based on the two Laue data sets, are shown for comparison. These include Arg 5, His 15, Phe 38, Asp 52, Tyr 53, Pro 70, Trp 108 and the four disulphide bridges.

[1]  R. Sweet,et al.  The hydrolytic water molecule in trypsin, revealed by time-resolved Laue crystallography , 1993, Science.

[2]  E. Dodson,et al.  A comparison of Laue and monochromatic X-ray analyses of a small-molecule crystal , 1989 .

[3]  J. W. Campbell,et al.  Evaluation of reflection intensities for the components of multiple Laue diffraction spots. II. Using the wavelength-normalization curve , 1993 .

[4]  D. Blow.  Now you see it, now you don't , 1993, Current Biology.

[5]  J R Helliwell,et al.  Distal pocket polarity in ligand binding to myoglobin: deoxy and carbonmonoxy forms of a threonine68(E11) mutant investigated by X-ray crystallography and infrared spectroscopy. , 1994, Biochemistry.

[6]  J. W. Campbell,et al.  Crystal structure determination of an organometallic compound from synchrotron radiation Laue diffraction photographs , 1988 .

[7]  John R. Helliwell,et al.  The emergence of the synchrotron Laue method for rapid data collection from protein crystals , 1993, Proceedings of the Royal Society of London. Series A: Mathematical and Physical Sciences.

[8]  John R. Helliwell,et al.  High-resolution crystallographic studies of native concanavalin A using rapid Laue data collection methods and the introduction of a monochromatic large-angle oscillation technique (LOT) , 1993 .

[9]  John R. Helliwell,et al.  The sensitivity of the synchrotron Laue method to small structural changes: binding studies of human carbonic anhydrase II (HCAII) , 1992 .

[10]  John R. Helliwell,et al.  The recording and analysis of synchrotron X-radiation Laue diffraction photographs , 1989 .

[11]  J. Helliwell,et al.  A comparison of Laue and monochromatic X‐ray analyses: the determination of the hydrogen‐atom positions of an organic small‐molecule crystal , 1989 .

[12]  Emil F. Pai,et al.  Time-resolved macromolecular crystallography , 1992 .

[13]  Nigel M. Allinson,et al.  Time-resolved synchrotron Laue diffraction and its application in structural molecular biology and materials science , 1992 .

[14]  T. A. Jones,et al.  A graphics model building and refinement system for macromolecules , 1978 .

[15]  John R. Helliwell,et al.  Multiplicity distribution of reflections in Laue diffraction , 1987 .

[16]  Y. Amemiya.  Imaging plate ‐ X‐ray area detector based on photostimulable phosphor , 1990 .

[17]  John R. Helliwell,et al.  A new protein crystallography station on the SRS wiggler beamline for very rapid Laue and rapidly tunable monochromatic experiments: I. Design principles, ray tracing and heat calculations , 1988 .

[18]  K. Moffat.  Time-resolved macromolecular crystallography , 1996 .

[19]  John R. Helliwell,et al.  Evaluation of reflection intensities for the components of multiple Laue diffraction spots by direct methods , 1993 .

[20]  Y. Amemiya,et al.  Imaging plate illuminates many fields , 1988, Nature.