You are cordially invited to join ……..
Jochen Zimmer
Professor, Molecular Physiology and
Biological Physics
School of Medicine
University of Virginia
Wednesday, August 16, 2023, 13:30 EDT
Molecular insights into polysaccharide secretion by ABC
transporters
https://bnl.zoomgov.com/meeting/register/vJItc-ysqj0oGZ57YFYVzEYm4se7kgZo66E
Abstract
O antigens are ubiquitous protective extensions of lipopolysaccharides in the
extracellular leaflet of the gram-negative outer membrane. Following
biosynthesis in the cytosol, the lipid-linked polysaccharide is transported to
the periplasm by the WzmWzt ABC transporter. Often, O antigen secretion
requires the chemical modification of its elongating terminus, which the ABC
transporter recognizes via a carbohydrate-binding domain (CBD). We identified
that methylated mannose or rhamnose caps the O antigen of Aquifex aeolicus.
Crystal and cryo electron microscopy structures reveal how WzmWzt recognizes
this cap between its carbohydrate and nucleotide-binding domains in a
nucleotide-free state. ATP binding induces drastic conformational changes of
its CBD, terminating interactions with the O antigen. Combined with mutagenesis
and functional analyses, our results elucidate critical steps in the
recognition and translocation of polysaccharides by ABC transporters.
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Vivian Stojanoff, PhD
Education, Training, Outreach
User Program
p 1(631) 344 8375
e [email protected]
w https://www.bnl.gov/ps/lifesciences/<https://www.bnl.gov/ps/lsbr/>
Address:
Center for Biomolecular Structure
National Synchrotron Light Source II
Building 745
Brookhaven National Laboratory
Upton NY 11973
Supporting Grants: CBMS is supported by NIH-NIGMS #P30GM133893, and by the
DOE-BER #KP1605010. Any work performed at NSLS-II is supported by DOE-BES
under contract # DE-SC0012704.
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