scholarly journals Functional importance of αIle-346 and αIle-348 in the catalytic sites of Escherichia coli ATP synthase

2016 ◽  
Vol 592 ◽  
pp. 27-37 ◽  
Author(s):  
Chao Zhao ◽  
Hiba Syed ◽  
Sherif S. Hassan ◽  
Vineet K. Singh ◽  
Zulfiqar Ahmad
Keyword(s):  
Escherichia Coli ◽  
Atp Synthase ◽  
Functional Importance ◽  
Catalytic Sites

scholarly journals Role of Charged Residues in the Catalytic Sites of Escherichia coli ATP Synthase

2011 ◽  
Vol 2011 ◽  
pp. 1-12 ◽  
Author(s):  
Zulfiqar Ahmad ◽  
Florence Okafor ◽  
Thomas F. Laughlin
Keyword(s):  
Escherichia Coli ◽  
Amino Acids ◽  
Atp Synthase ◽  
Electrostatic Interactions ◽  
Critical Role ◽  
Phosphate Binding ◽  
Catalytic Sites ◽  
Charged Residues ◽  
Positively Charged

Here we describe the role of charged amino acids at the catalytic sites of Escherichia coli ATP synthase. There are four positively charged and four negatively charged residues in the vicinity of of E. coli ATP synthase catalytic sites. Positive charges are contributed by three arginine and one lysine, while negative charges are contributed by two aspartic acid and two glutamic acid residues. Replacement of arginine with a neutral amino acid has been shown to abrogate phosphate binding, while restoration of phosphate binding has been accomplished by insertion of arginine at the same or a nearby location. The number and position of positive charges plays a critical role in the proper and efficient binding of phosphate. However, a cluster of many positive charges inhibits phosphate binding. Moreover, the presence of negatively charged residues seems a requisite for the proper orientation and functioning of positively charged residues in the catalytic sites. This implies that electrostatic interactions between amino acids are an important constituent of initial phosphate binding in the catalytic sites. Significant loss of function in growth and ATPase activity assays in mutants generated through charge modulations has demonstrated that precise location and stereochemical interactions are of paramount importance.

scholarly journals Comprehensive Alanine-scanning Mutagenesis of Escherichia coli CsrA Defines Two Subdomains of Critical Functional Importance

2006 ◽  
Vol 281 (42) ◽  
pp. 31832-31842
Author(s):  
Jeffrey Mercante ◽  
Kazushi Suzuki ◽  
Xiaodong Cheng ◽  
Paul Babitzke ◽  
Tony Romeo
Keyword(s):  
Escherichia Coli ◽  
Functional Importance ◽  
Alanine Scanning Mutagenesis ◽  
Alanine Scanning
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