scholarly journals Conversion of a magnesium binding site into a zinc binding site by a single amino acid substitution in Escherichia coli alkaline phosphatase.

1993 ◽  
Vol 268 (29) ◽  
pp. 21497-21500
Author(s):  
J.E. Murphy ◽  
X Xu ◽  
E.R. Kantrowitz
Keyword(s):  
Escherichia Coli ◽  
Alkaline Phosphatase ◽  
Amino Acid ◽  
Binding Site ◽  
Amino Acid Substitution ◽  
Single Amino Acid Substitution ◽  
Zinc Binding ◽  
Single Amino Acid ◽  
Magnesium Binding ◽  
Zinc Binding Site

scholarly journals A Single Amino Acid Substitution in a Mannosyltransferase, WbdA, Converts the Escherichia coli O9 Polysaccharide into O9a: Generation of a New O-Serotype Group

2000 ◽  
Vol 182 (9) ◽  
pp. 2567-2573 ◽  
Author(s):  
Nobuo Kido ◽  
Hidemitsu Kobayashi
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Amino Acid Substitution ◽  
Site Directed Mutagenesis ◽  
Single Amino Acid Substitution ◽  
Single Amino Acid ◽  
Directed Mutagenesis ◽  
E Coli ◽  
Chimeric Genes ◽  
Functional Studies

ABSTRACT wbdA is a mannosyltransferase gene that is involved in synthesis of the Escherichia coli O9a polysaccharide, a mannose homopolymer with a repeating unit of 2-αMan-1,2-αMan-1,3-αMan-1,3-αMan-1. The equivalent structural O polysaccharide in the E. coli O9 andKlebsiella O3 strains is 2-αMan-1,2-αMan-1,2-αMan-1,3-αMan-1,3-αMan-1, with an excess of one mannose in the 1,2 linkage. We have cloned wbdAgenes from these O9 and O3 strains and shown by genetic and functional studies that wbdA is the only gene determining the O-polysaccharide structure of O9 or O9a. Based on functional analysis of chimeric genes and site-directed mutagenesis, we showed that a single amino acid substitution, C55R, in WbdA of E. coli O9 converts the O9 polysaccharide into O9a. DNA sequencing revealed the substitution to be conserved in other E. coli O9a strains. The reverse substitution, R55C, in WbdA of E. coli O9a resulted in lipopolysaccharide synthesis showing no ladder profile instead of the conversion of O9a to O9. This suggests that more than one amino acid substitution in WbdA is required for conversion from O9a to O9.

A single amino acid substitution can restore the solubility of aggregated colicin A mutants in Escherichia coli

1994 ◽  
Vol 7 (12) ◽  
pp. 1495-1500 ◽  
Author(s):  
Jacques Izard ◽  
Michael W. Parker ◽  
Martlne Chartier ◽  
Denis Ducheé ◽  
Daniel Baty
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Amino Acid Substitution ◽  
Single Amino Acid Substitution ◽  
Single Amino Acid

scholarly journals NDM-4 Metallo-β-Lactamase with Increased Carbapenemase Activity from Escherichia coli

2012 ◽  
Vol 56 (4) ◽  
pp. 2184-2186 ◽  
Author(s):  
Patrice Nordmann ◽  
Anne E. Boulanger ◽  
Laurent Poirel
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Amino Acid Substitution ◽  
Active Sites ◽  
Hydrolytic Activity ◽  
Single Amino Acid Substitution ◽  
Single Amino Acid ◽  
Amino Acid Substitutions ◽  
Content Type

ABSTRACTA clinicalEscherichia coliisolate resistant to all β-lactams, including carbapenems, expressed a novel metallo-β-lactamase (MBL), NDM-4, differing from NDM-1 by a single amino acid substitution (Met154Leu). NDM-4 possessed increased hydrolytic activity toward carbapenems and several cephalosporins compared to that of NDM-1. This amino acid substitution was not located in the known active sites of NDM-1, indicating that remote amino acid substitutions might also play a role in the extended activity of this MBL.

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