Site-directed mutants of the cytochrome bo ubiquinol oxidase of Escherichia coli: Amino acid substitutions for two histidines that are putative CuB ligands

Biochemistry ◽  
1993 ◽  
Vol 32 (43) ◽  
pp. 11524-11529 ◽  
Author(s):  
Melissa W. Calhoun ◽  
John J. Hill ◽  
Laura J. Lemieux ◽  
W. John Ingledew ◽  
James O. Alben ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Amino Acid Substitutions ◽  
Cytochrome Bo ◽  
Ubiquinol Oxidase

scholarly journals Amino acid substitutions and alteration in cation specificity in the melibiose carrier of Escherichia coli.

1988 ◽  
Vol 263 (28) ◽  
pp. 14276-14280 ◽  
Author(s):  
T Kawakami ◽  
Y Akizawa ◽  
T Ishikawa ◽  
T Shimamoto ◽  
M Tsuda ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Amino Acid Substitutions

scholarly journals Effects of Amino Acid Substitutions at Conserved and Acidic Residues within Region 1.1 of Escherichia coli ς70

2000 ◽  
Vol 182 (1) ◽  
pp. 221-224 ◽  
Author(s):  
Christina Wilson Bowers ◽  
Andrea McCracken ◽  
Alicia J. Dombroski
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Aspartic Acid ◽  
Transcription Initiation ◽  
Amino Acid Substitutions ◽  
Conserved Residues ◽  
Acidic Residues

ABSTRACT Amino acid substitutions in Escherichia coliς70 were generated and characterized in an analysis of the role of region 1.1 in transcription initiation. Several acidic and conserved residues are tolerant of substitution. However, replacement of aspartic acid 61 with alanine results in inactivity caused by structural and functional thermolability.

Structural and functional consequences of single amino acid substitutions in the pyrimidine base binding pocket of Escherichia coli CMP kinase

FEBS Journal ◽  
2007 ◽  
Vol 274 (13) ◽  
pp. 3363-3373 ◽  
Author(s):  
Augustin Ofiteru ◽  
Nadia Bucurenci ◽  
Emil Alexov ◽  
Thomas Bertrand ◽  
Pierre Briozzo ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Binding Pocket ◽  
Single Amino Acid ◽  
Amino Acid Substitutions ◽  
Pyrimidine Base ◽  
Functional Consequences

scholarly journals Investigation of the Role of Electrostatic Charge in Activation of the Escherichia coli Response Regulator CheY

2003 ◽  
Vol 185 (21) ◽  
pp. 6385-6391 ◽  
Author(s):  
Jenny G. Smith ◽  
Jamie A. Latiolais ◽  
Gerald P. Guanga ◽  
Sindhura Citineni ◽  
Ruth E. Silversmith ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Signal Transduction ◽  
Amino Acid ◽  
Active Site ◽  
Response Regulator ◽  
Residual Activity ◽  
Phosphoryl Group ◽  
Sensor Kinase ◽  
Amino Acid Substitutions ◽  
Flagellar Rotation

ABSTRACT In a two-component regulatory system, an important means of signal transduction in microorganisms, a sensor kinase phosphorylates a response regulator protein on an aspartyl residue, resulting in activation. The active site of the response regulator is highly charged (containing a lysine, the phosphorylatable aspartate, two additional aspartates involved in metal binding, and an Mg2+ ion), and introduction of the dianionic phosphoryl group results in the repositioning of charged moieties. Furthermore, substitution of one of the Mg2+-coordinating aspartates with lysine or arginine in the Escherichia coli chemotaxis response regulator CheY results in phosphorylation-independent activation. In order to examine the consequences of altered charge distribution for response regulator activity and to identify possible additional amino acid substitutions that result in phosphorylation-independent activation, we made 61 CheY mutants in which residues close to the site of phosphorylation (Asp57) were replaced by various charged amino acids. Most substitutions (47 of 61) resulted in the complete loss of CheY activity, as measured by the inability to support clockwise flagellar rotation. However, 10 substitutions, all introducing a new positive charge, resulted in the loss of chemotaxis but in the retention of some clockwise flagellar rotation. Of the mutants in this set, only the previously identified CheY13DK and CheY13DR mutants displayed clockwise activity in the absence of the CheA sensor kinase. The absence of negatively charged substitution mutants with residual activity suggests that the introduction of additional negative charges into the active site is particularly deleterious for CheY function. Finally, the spatial distribution of positions at which amino acid substitutions are functionally tolerated or not tolerated is consistent with the presently accepted mechanism of response regulator activation and further suggests a possible role for Met17 in signal transduction by CheY.

scholarly journals Mutations in the uncE gene affecting assembly of the c-subunit of the adenosine triphosphatase of Escherichia coli

1983 ◽  
Vol 211 (3) ◽  
pp. 717-726 ◽  
Author(s):  
D A Jans ◽  
A L Fimmel ◽  
L Langman ◽  
L B James ◽  
J A Downie ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Cell Membrane ◽  
Dna Sequences ◽  
Adenosine Triphosphatase ◽  
Gene Dosage ◽  
Base Change ◽  
Amino Acid Substitutions ◽  
Helical Hairpin ◽  
C Subunit

The amino acid substitutions in the mutant c-subunits of Escherichia coli F1F0-ATPase coded for by the uncE429, uncE408 and uncE463 alleles affect the incorporation of these proteins into the cell membrane. The DNA sequence of the uncE429 allele differed from normal in that a G leads to A base change occurred at nucleotide 68 of the uncE gene, resulting in glycine being replaced by aspartic acid at position 23 in the c-subunit. The uncE408 and uncE463 mutant DNA sequences were identical and differed from normal in that a C leads to T base change occurred at nucleotide 91 of the uncE gene, resulting in leucine being replaced by phenylalanine at position 31 in the c-subunit. An increased gene dosage of the uncE408 or uncE463 alleles resulted in the incorporation into the membranes of the mutant c-subunits. The results are discussed in terms of the ‘Helical Hairpin Hypothesis’ of Engelman & Steitz [(1981) Cell 23,411-422].

Amino acid substitutions in the ε-subunit of the F1F0-ATPase of Escherichia coli

1987 ◽  
Vol 890 (2) ◽  
pp. 195-204 ◽  
Author(s):  
G.B. Cox ◽  
L. Hatch ◽  
D. Webb ◽  
A.L. Fimmel ◽  
Z.-H. Lin ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Amino Acid Substitutions ◽  
F1f0 Atpase
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