Conformational changes of FtsZ reported by tryptophan mutants.
Abstract
E. coli FtsZ has no native tryptophan. We showed previously that the mutant FtsZ L68W
gave a 2.5-fold increase in trp fluorescence when assembly was induced by GTP. L68
is probably buried in the protofilament interface upon assembly, causing the fluorescence
increase. In the present study we introduced trp residues at several other locations
and examined them for assembly-induced fluorescence changes. L189W, located on helix
H7 and buried between the N- and C-terminal subdomains, showed a large fluorescence
increase, comparable to L68W. This may reflect a shift or rotation of the two subdomains
relative to each other. L160W showed a smaller increase in fluorescence, and Y222W
a decrease in fluorescence, upon assembly. These two are located on the surface of
the N and C subdomains, near the domain boundary. The changes in fluorescence may
reflect movements of the domains or of nearby side chains. We prepared a double mutant
Y222W/S151C and coupled ATTO-655 to the cys. The Cα of trp in the C-terminal subdomain
was 10 Å away from that of the cys in the N-terminal subdomain, permitting the ATTO
to make van der Waals contact with the trp. The ATTO fluorescence showed strong tryptophan-induced
quenching. The quenching was reduced following assembly, consistent with a movement
apart of the two subdomains. Movements of one to several angstroms are probably sufficient
to account for the changes in trp fluorescence and trp-induced quenching of ATTO.
Assembly in GDP plus DEAE dextran produces tubular polymers that are related to the
highly curved, mini-ring conformation. No change in trp fluorescence was observed
upon assembly of these tubes, suggesting that the mini-ring conformation is the same
as that of a relaxed, monomeric FtsZ.
Type
Journal articleSubject
AcrylamideTryptophan
Bacterial Proteins
Cytoskeletal Proteins
Microscopy, Electron
Spectrometry, Fluorescence
Protein Conformation
Mutation
Models, Molecular
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https://hdl.handle.net/10161/16460Published Version (Please cite this version)
10.1021/bi200106dPublication Info
Chen, Yaodong; & Erickson, Harold P (2011). Conformational changes of FtsZ reported by tryptophan mutants. Biochemistry, 50(21). 10.1021/bi200106d. Retrieved from https://hdl.handle.net/10161/16460.This is constructed from limited available data and may be imprecise. To cite this
article, please review & use the official citation provided by the journal.
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Show full item recordScholars@Duke
Harold Paul Erickson
James B. Duke Distinguished Professor Emeritus
Recent research has been on cytoskeleton (eukaryotes and bacteria); a skirmish to
debunk the irisin story; a reinterpretation of proposed multivalent binders of the
coronavirus spike protein. I have also published an ebook on "Principles of Protein-Protein
Association" suitable for a course module or individual learning.

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