Acta Crystallographica Section D

Biological Crystallography

Volume 69, Part 10 (October 2013)


research papers



Acta Cryst. (2013). D69, 2017-2026    [ doi:10.1107/S0907444913018015 ]

High-resolution structure of a papaya plant-defence barwin-like protein solved by in-house sulfur-SAD phasing

J. Huet, E. J. Teinkela Mbosso, S. Soror, F. Meyer, Y. Looze, R. Wintjens and A. Wohlkönig

Abstract: The first crystal structure of a barwin-like protein, named carwin, has been determined at high resolution by single-wavelength anomalous diffraction (SAD) phasing using the six intrinsic S atoms present in the protein. The barwin-like protein was purified from Carica papaya latex and crystallized in the orthorhombic space group P212121. Using in-house Cu K[alpha] X-ray radiation, 16 cumulative diffraction data sets were acquired to increase the signal-to-noise level and thereby the anomalous scattering signal. A sequence-database search on the papaya genome identified two carwin isoforms of 122 residues in length, both containing six S atoms that yield an estimated Bijvoet ratio of 0.93% at 1.54 Å wavelength. A systematic analysis of data quality and redundancy was performed to assess the capacity to locate the S atoms and to phase the data. It was observed that the crystal decay was low during data collection and that successful S-SAD phasing could be obtained with a relatively low data multiplicity of about 7. Using a synchrotron source, high-resolution data (1 Å) were collected from two different crystal forms of the papaya latex carwin. The refined structures showed a central [beta]-barrel of six strands surrounded by several [alpha]-helices and loops. The [beta]-barrel of carwin appears to be a common structural module that is shared within several other unrelated proteins. Finally, the possible biological function of the protein is discussed.

PDB references: 4jp6 and 4jp7

Keywords: sulfur-SAD phasing; barwin-like protein; carwin; Carica papaya.


pdfdisplay filedownload file

Portable Document Format (PDF) file
[ doi:10.1107/S0907444913018015/tz5031sup1.pdf ]
Supplementary material


Notes:

To open or display or play some files, you may need to set your browser up to use the appropriate software. See the full list of file types for an explanation of the different file types and their related mime types and, where available links to sites from where the appropriate software may be obtained.

The download button will force most browsers to prompt for a file name to store the data on your hard disk.

Where possible, images are represented by thumbnails.

 bibliographic record in  format

  Find reference:   Volume   Page   
  Search:     From   to      Advanced search

Copyright © International Union of Crystallography
IUCr Webmaster