Crystal twinning of human MD-2 recognizing endotoxin cores of lipopolysaccharide
Twinning of crystals causes overlapping of two or more reciprocal lattice points, and hence structure amplitudes for a single crystalline domain are hardly obtained from X‐ray diffraction intensities. MD‐2 protein forms a stable complex with Toll‐like receptor 4 and recognizes bacterial lipopolysacc...
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Published in | Journal of synchrotron radiation Vol. 15; no. 3; pp. 262 - 265 |
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Main Authors | , |
Format | Journal Article |
Language | English |
Published |
5 Abbey Square, Chester, Cheshire CH1 2HU, England
International Union of Crystallography
01.05.2008
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Subjects | |
Online Access | Get full text |
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Summary: | Twinning of crystals causes overlapping of two or more reciprocal lattice points, and hence structure amplitudes for a single crystalline domain are hardly obtained from X‐ray diffraction intensities. MD‐2 protein forms a stable complex with Toll‐like receptor 4 and recognizes bacterial lipopolysaccharide (LPS). Excessive immune responses activated by LPS cause septic shocks. Saccharide‐trimmed human MD‐2 crystallizes in the tetragonal form with apparent Laue symmetry of 4/mmm, and diffraction intensities from these crystals indicate crystal twinning. The crystal consists of two different domains, A and B. The cA axis of domain A coincides with the cB axis of domain B with a smaller lattice, and the aA axis corresponds to the (aB + bB) axis. This twinning severely imposes difficulty in structure determination. Through optimization of cryoprotectant, domain A was thoroughly transformed into domain B. The crystal containing only domain B is in space group P41212 with one MD‐2 molecule in the asymmetric unit. The structure of this form of MD‐2 as well as its complex with antiendotoxic lipid IVa was successfully determined using the multiple isomorphous replacement method. |
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Bibliography: | istex:0E3A54993A246294428C870191227D8C7AAA183D ArticleID:JSYYS5015 ark:/67375/WNG-11GV34L1-D ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 1600-5775 0909-0495 1600-5775 |
DOI: | 10.1107/S0909049507056531 |