scholarly journals Activation of the SN2 Reaction by Adjacent π Systems: The Critical Role of Electrostatic Interactions and of Dissociative Character

2016 ◽  
Vol 138 (3) ◽  
pp. 734-737 ◽  
Author(s):  
Raphaël Robiette ◽  
Tran Trieu-Van ◽  
Varinder K. Aggarwal ◽  
Jeremy N. Harvey
Keyword(s):  
Electrostatic Interactions ◽  
Critical Role ◽  
Sn2 Reaction

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.

The Role of the SLP in Autism Spectrum Disorder Screening and Assessment

2008 ◽  
Vol 15 (2) ◽  
pp. 50-59 ◽  
Author(s):  
Amy Philofsky
Keyword(s):  
Language Development ◽  
Critical Role ◽  
Children With Autism ◽  
Autism Spectrum ◽  
Children With Asd ◽  
Prevalence Estimates ◽  
Notable Increase ◽  
Screening Assessment ◽  
Critical Components

AbstractRecent prevalence estimates for autism have been alarming as a function of the notable increase. Speech-language pathologists play a critical role in screening, assessment and intervention for children with autism. This article reviews signs that may be indicative of autism at different stages of language development, and discusses the importance of several psychometric properties—sensitivity and specificity—in utilizing screening measures for children with autism. Critical components of assessment for children with autism are reviewed. This article concludes with examples of intervention targets for children with ASD at various levels of language development.

A critical role of iNOS-derived Nitric Oxide (NO) and progesterone in implantation

1998 ◽  
Vol 5 (1) ◽  
pp. 115A-115A
Author(s):  
K CHWALISZ ◽  
E WINTERHAGER ◽  
T THIENEL ◽  
R GARFIELD
Keyword(s):  
Nitric Oxide ◽  
Critical Role

Bridging the Gap between Ethical Climate and Nurses’ Service Behaviors: the Critical Role of Professional Well-Being

2018 ◽  
Vol 20 (3) ◽  
pp. 99-110
Author(s):  
Na Zhang ◽  
Jingjing Li ◽  
Xing Bu ◽  
Zhenxing Gong ◽  
Gilal Faheem Gul
Keyword(s):  
Ethical Climate ◽  
Critical Role ◽  
Well Being
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