Accurate Estimation of pKb Values for Amino Groups from Surface Electrostatic Potential (VS,min) Calculations: The Isoelectric Points of Amino Acids as a Case Study

2020 ◽  
Vol 60 (3) ◽  
pp. 1445-1452 ◽  
Author(s):  
Jacinto Sandoval-Lira ◽  
Gustavo Mondragón-Solórzano ◽  
Leonardo I. Lugo-Fuentes ◽  
Joaquín Barroso-Flores
Keyword(s):  
Amino Acids ◽  
Electrostatic Potential ◽  
Accurate Estimation ◽  
Amino Groups ◽  
Isoelectric Points ◽  
Surface Electrostatic Potential

scholarly journals SARS-CoV-2 B.1.617 Indian variants: are electrostatic potential changes responsible for a higher transmission rate?

2021 ◽  
Author(s):  
Stefano Pascarella ◽  
Massimo Ciccozzi ◽  
Davide Zella ◽  
Martina Bianchi ◽  
Francesca Benedetti ◽  
...  
Keyword(s):  
Amino Acids ◽  
Electrostatic Potential ◽  
Transmission Rate ◽  
Virus Transmission ◽  
Major Effect ◽  
Spike Protein ◽  
Charged Amino Acids ◽  
Potential Impact ◽  
Surface Electrostatic Potential ◽  
Positively Charged

Lineage B.1.617+, also known as G/452R.V3, is a recently described SARS-CoV-2 variant under investigation (VUI) firstly identified in October 2020 in India. As of May 2021, three sublineages labelled as B.1.617.1, B.1.617.2 and B.1.617.3 have been already identified, and their potential impact on the current pandemic is being studied. This variant has 13 amino acid changes, three in its spike protein, which are currently of particular concern: E484Q, L452R and P681R. Here we report a major effect of the mutations characterizing this lineage, represented by a marked alteration of the surface electrostatic potential (EP) of the Receptor Binding Domain (RBD) of the spike protein. Enhanced RBD-EP is particularly noticeable in the B.1.617.2 sublineage, which shows multiple replacements of neutral or negatively-charged amino acids with positively-charged amino acids. We here hypothesize that this EP change can favor the interaction between the B.1.617+ RBD and the negatively-charged ACE2 thus conferring a potential increase in the virus transmission.

Measurement System of Surface Electrostatic Potential on Insulation Board in Vacuum and its Application

2012 ◽  
Vol 132 (1) ◽  
pp. 95-100
Author(s):  
Hiroshi Morita ◽  
Ayumu Hatanaka ◽  
Toshiyuki Yokosuka ◽  
Yoshitaka Seki ◽  
Yoshiaki Tsumuraya ◽  
...  
Keyword(s):  
Electrostatic Potential ◽  
Measurement System ◽  
Surface Electrostatic Potential

scholarly journals The principle of formaldehyde, alcohol, and acetone titrations. With a discussion of the proof and implication of the zwitterion conception

1934 ◽  
Vol 115 (792) ◽  
pp. 121-141 ◽  
Keyword(s):  
Amino Acids ◽  
Carboxyl Groups ◽  
Recent Discussion ◽  
Amino Groups ◽  
Chemical Methods ◽  
Titration Method ◽  
Physico Chemical ◽  
Empirical Argument ◽  
Chemical Evidence

Consideration of the implications of the zwitterion hypothesis of Bjerrum (1923) makes it desirable to state afresh the principles underlying the methods commonly employed in the titration of amino-acids. Deductions of considerable theoretical importance, cf., e. g ., Calvery (1933) are still being made on the supposition that the alkalimetric formaldehyde titration method of Sørensen (1907) and the corresponding alcohol method of Foreman (1920) and of Willstätter and Waldschmidt-Leitz (1921) estimate the carboxyl groups of amino-acids whilst the acidimetric acetone titration of Linderstrøm-Lang (1928) estimates the amino-groups. Yet the zwitterion hypothesis indicates that this assumption is the reverse of the truth. Discussion is greatly facilitated by collective consideration of recent physico-chemical evidence clarifying the principles upon which these common bio-chemical methods rest. In a recent discussion of two of the titrimetric methods (Van Slyke and Kirk, 1933) the existence of this evidence is ignored, so that it becomes necessary to systematize and elaborate the empirical argument of these authors in the light of the relevant investigations of Grünhut (1919), Cray and Westrip (1925), Michaelis and Mizutani (1925), Birch and Harris (1930, b ), and Levy (1933). At the same time new and useful developments are indicated.

Automated Determination of Free Amino Groups in Serum and Plasma Using 2,4,6-Trinitrobenzene Sulfonate

1969 ◽  
Vol 15 (9) ◽  
pp. 891-901 ◽  
Author(s):  
D W Palmer ◽  
T Peters
Keyword(s):  
Amino Acids ◽  
Free Amino Acids ◽  
Free Amino ◽  
Clinical Applications ◽  
Amino Groups ◽  
Automated Method ◽  
Total Free Amino Acids ◽  
Colored Complexes ◽  
Automated Determination

Abstract A simple automated method is described for determining the level of total free amino acids in the blood. The method utilizes the AutoAnalyzer, and is based on the formation of colored complexes by uniting free amino groups with 2,4,6-trinitrobenzene sulfonate (TNBS). Proteins do not interfere because the free amino acids are first separated by dialysis. Characteristics of the reaction and potential clinical applications of the procedure are discussed.

Frameworks of Transition Metals and Linkers with Two or More Functional Groups

2000 ◽  
Vol 658 ◽  
Author(s):  
Slavi C. Sevov
Keyword(s):  
Amino Acids ◽  
Transition Metals ◽  
Functional Groups ◽  
Organic Molecules ◽  
Layered Structures ◽  
Amino Groups ◽  
Effect Of Ph ◽  
Open Framework ◽  
Acidic Conditions ◽  
New Compounds

ABSTRACTHybrid inorganic/organic materials with open-framework or layered structures are known for many transition metals linked by functionalized organic molecules such as organic diphosphonates, polycarboxylates, polynitriles, etc., species with more than one equivalent functional groups. We have studied the effect of pH on such a system of cobaltmethylenediphosphonate and report three new compounds, Na3Co[(O3PCH2PO3)(OH)],Na2Co(O3PCH2PO3)•H2O, and Co2[(O3PCH2PO3)(H2O)], that form at very basic, moderately basic, and acidic conditions, respectively. More interestingstructural chemistry should be expected from linkers with two or more different functionalities. Both the carboxylic and phosphonic groups in carboxyethylphosphonic acid are used to coordinate to cobalt or calcium atoms in the new compounds Co3(O3PCH2CH2COO)2•6H2O and Ca(O3PCH2CH2COOH)•H2O. Taking one more step further in complexity we have also studied linkers with three different functional groups, phosphonated amino acids. The structures of two new compounds, Zn(O3PCH2CH(NH3)COO) and Zn(O3PCH2CH2CH(NH3)COO), are threedimensional frameworks made of zinccoordinated by both the carboxylic and phosphonic ends of the organic molecules. The amino groups are protonated and terminal in the voids of the frameworks.

Condensation de la poly-L-lysine et de la poly- L-ornithine avec des dérivés de bases puriques et de sulfamides

1969 ◽  
Vol 47 (19) ◽  
pp. 3641-3646 ◽  
Author(s):  
Louis Berlinguet ◽  
Jacky Gautier
Keyword(s):  
Aqueous Solution ◽  
Amino Acids ◽  
Free Amino ◽  
Sulfonyl Chloride ◽  
Amino Groups ◽  
Carbodiimide Method

Free ε-amino groups of poly-L-lysine and poly-L-ornithine were alkylated in aqueous solution with 6-chloropurine and 6-chloropurine-riboside, were acylated with 4-acetylamino benzene sulfonyl chloride, and were condensed with N-(4-acetylamino benzene sulfonyl)-glycine using carbodiimide method. Approximately 50% of the free amino groups of the basic polypetides were substituted. The same method was used to prepare poly-α-amino acids bearing radioactive substituants.

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