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Acid-induced loss of functional properties of bacterial cell division protein FtsZ: Evidence for an alternative conformation at acidic pH

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Title Acid-induced loss of functional properties of bacterial cell division protein FtsZ: Evidence for an alternative conformation at acidic pH
 
Creator SANTRA, MK
PANDA, D
 
Subject escherichia-coli
gtp hydrolysis
ruthenium red
molten globule
ring structure
in-vitro
tubulin
intermediate
apomyoglobin
binding
ftsz assembly dynamics
unfolding of ftsz
gtp hydrolysis
gtp binding
molten globule state
intermediate
productive aggregates
lifetime
 
Description Several types of bacteria live in highly acidic environments. Since the assembly of FtsZ is important for bacterial cytokinesis, the effects of pH on the assembly and structural properties of FtsZ were examined. FtsZ retained GTP binding ability but lost GTPase activity at pH 2.5. In the presence of GTP, FtsZ formed protofilaments at pH 7 while it formed aggregates instead of protofilaments at pH 2.5, indicating that GTP hydrolysis is important for the assembly of FtsZ into protofilaments. Further, the acid-inactivated state of FtsZ recovered its structural and functional properties upon refolding at pH 7, indicating that the cellular functions of FtsZ may be restored after removal of the external stress. In addition, the affinity of 1-anilinonaphthalene-8-sulfonic acid (ANS) binding to FtsZ was found to be higher at pH 2.5 than at pH 7. FtsZ-ANS complex had a higher quantum yield and lifetime at pH 2.5 than at pH 7. However, the secondary structures of FtsZ were similar at pH 7 and 2.5, indicating that FtsZ attained an alternatively folded state (A) at pH 2.5, which has some characteristics of a molten-globule-like state. The A state was more stable than the native state (N) against urea-induced unfolding. The transition from N to A state involves the formation of aggregates of FtsZ (1). The association of FtsZ monomers occurred in the narrow pH range (3.2-2.8) and it was found to be a fully reversible process. The results suggest that a productive intermediate M forms in the acid-induced unfolding pathway of FtsZ and that the unfolding pathway may be minimally described as N reversible arrow I reversible arrow A. Proteins 2007;67:177-188. (c) 2007 Wiley-Liss, Inc.
 
Publisher WILEY-LISS
 
Date 2011-09-01T12:54:26Z
2011-12-26T12:59:39Z
2011-12-27T05:52:15Z
2011-09-01T12:54:26Z
2011-12-26T12:59:39Z
2011-12-27T05:52:15Z
2007
 
Type Article
 
Identifier PROTEINS-STRUCTURE FUNCTION AND BIOINFORMATICS, 67(1), 177-188
0887-3585
http://dx.doi.org/10.1002/prot.21178
http://dspace.library.iitb.ac.in/xmlui/handle/10054/12783
http://hdl.handle.net/10054/12783
 
Language en