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Vaccinia Virus H3 Envelope Protein, a Major Target of Neutralizing Antibodies, Exhibits a Glycosyltransferase Fold and Binds UDP-Glucose

Vaccinia Virus H3 Envelope Protein, a Major Target of Neutralizing Antibodies, Exhibits a Glycosyltransferase Fold and Binds UDP-GlucoseThe highly conserved H3 poxvirus protein is a major target of the human antibody response against poxviruses and is likely a key contributor to protection against infection. Here, we present the crystal structure of H3 from vaccinia virus at a 1.9-Å resolution. H3 looks like a glycosyltransferase, a family of enzymes that transfer carbohydrate molecules to a variety of acceptor substrates. Like glycosyltransferases, H3 binds UDP-glucose, as shown by saturation transfer difference (STD) nuclear magnetic resonance (NMR) spectroscopy, and this binding requires Mg2+. Mutation of the glycosyltransferase-like metal ion binding motif in H3 greatly diminished its binding to UDP-glucose. We found by flow cytometry that H3 binds to the surface of human cells but does not bind well to cells that are deficient in surface glycosaminoglycans. STD NMR experiments using a heparin sulfate decasaccharide confirmed that H3 binds heparin sulfate. We propose that a surface of H3 with an excess positive charge may be the binding site for heparin. Heparin binding and glycosyltransferase activity may be involved in the function of H3 in the poxvirus life cycle.

J Virol. 2016 Apr 29;90(10):5020-30.
doi: 10.1128/JVI.02933-15.
Print 2016 May 15.


Journal of Virology.

© 2016 American Society for Microbiology.

  Singh K, Gittis AG, Gitti RK, Ostazeski SA, Su HP, Garboczi DN.

Another SBC Highlight:

Structural basis of cohesin cleavage by separase
Crystal structure of the human sterol transporter ABCG5/ABCG8


ATP binding cassette (ABC) transporters play critical roles in maintaining sterol balance in higher eukaryotes. The ABCG5/ ABCG8 heterodimer (G5G8) mediates excretion of neutral sterols in liver and intestines.


Nature. 2016 May 4;533(7604):561-4.
doi: 10.1038/nature17666

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SBC Announcements:


19-ID Pilatus Detector

SBC is pleased to announce the introduction of a Pilatus 3 X 6M detector into the User Program at beamline 19-ID.
Data collected by our users has been of outstanding quality.




19-BM Rebotic sample mounter available

A robot is now available for use at beamline 19-BM. The sample dewar accommodates ten Unipuck magazines; pins must be 18mm in length and use either SSRL or ALS bases. Experienced users may now request remote access to 19-BM when applying for beamtime.




ALSO: Please Be Aware...!


APS requests the Experimental Safety Approval Form (ESAF) be submitted at least seven days prior to your scheduled beamtime.


Failure to submit your ESAF in advance may result in delaying the beginning of your experiment.


Rapid Access Beamtime Available:

SBC Beamtime Request System

The on-line SBC Beamtime Request System allows users to view available beamtime on 19-ID and 19-BM, and to submit a request for rapid beamtime allocation.

Beamtime is available to the research community via a peer reviewed proposal system; it is supported by the U.S. Department of Energy, Office of Biological and Environmental Research.

Current Beamline Statistics:

APS PDB Depositions from BioSync
SBC Sector 19 2014 2015 2016 TOTAL
PDB Depositions 263 36 223 25 47 10 4743

APS Publications Database:

Publications Total
SBC-CAT Publication List: 19-ID 1405
SBC-CAT Publication List: 19-BM 519
SBC-CAT Publication List: ALL
APS Publications Database

MCSG / APCF Announcements:


Beginning August 01, 2015 the Midwest Center for Structural Genomics (MCSG) will start accepting applications for access to the MCSG User Resource.


MCSG's structure determination platform is well established, and combines technologies, robotics and expertise for gene cloning, protein production, and crystallization, as well as biochemical and biophysical characterization.


For further information, please contact Andrzej Joachimiak.


Future Meetings:


Protein Society: 30th Anniversary Symposium

July 16-19, 2016

Hyatt Regency Baltimore; Baltimore MD


Diffraction Methods in Structural Biology; Gordon Research Conference

July 17-22, 2016

Bates College; Lewiston ME


American Crystallographic Association, 2016

July 22-26, 2016

Downtown Sheraton Hotel; Denver CO


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