scholarly journals A synthetic 70-amino acid residue analog of ribonuclease S-protein with enzymic activity.

1975 ◽  
Vol 250 (3) ◽  
pp. 889-904
Author(s):  
B Gutte
Keyword(s):  
Amino Acid ◽  
Amino Acid Residue ◽  
Enzymic Activity ◽  
S Protein

scholarly journals A critical amino acid residue, Asp446, in UDP-glucuronosyltransferase

1997 ◽  
Vol 325 (3) ◽  
pp. 587-591 ◽  
Author(s):  
Hidetomo IWANO ◽  
Hiroshi YOKOTA ◽  
Satoru OHGIYA ◽  
Naomi YOTUMOTO ◽  
Akira YUASA
Keyword(s):  
Amino Acid ◽  
Amino Acid Residue ◽  
Amino Acid Substitution ◽  
Critical Role ◽  
Enzymic Activity ◽  
Male Rat ◽  
Transferase Activity ◽  
Rt Pcr ◽  
Taq Polymerase ◽  
Udp Glucuronosyltransferase

An amino acid residue, Asp446, was found to be essential for the enzymic activity of UDP-glucuronosyltransferase (UGT). We obtained a rat phenol UGT (UGT1*06) cDNA (named Ysh) from male rat liver by reverse-transcription (RT)-PCR using pfu polymerase. A mutant Ysh having two different bases, A1337G and G1384A (named Ysh A1337GC1384A), that result in two amino acid substitutions, D446G and V462M, was obtained by RT-PCR using Taq polymerase. Ysh was expressed functionally in microsomes of Saccharomyces cerevisiae strain AH22. However, the expressed protein from Ysh A1337GG1384A had no transferase activity. Two other mutant cDNAs with Ysh A1337G having one changed base, A1337G, resulting in one amino acid substitution, D446G, and Ysh G1384A having a changed base, G1384A, resulting in an amino acid substitution, V462M, were constructed and expressed in the yeast. The expressed protein from Ysh G1384A (named Ysh V462M) exhibited enzymic activity, but the one from Ysh A1337G (named Ysh D446G) did not show any activity at all. Asp446 was conserved in all UGTs and UDP-galactose:ceramide galactosyltransferases reported, suggesting that Asp446 plays a critical role in each enzyme.

scholarly journals Medical Countermeasures Analysis of 2019-nCoV and Vaccine Risks for Antibody-Dependent Enhancement (ADE)

2020 ◽  
Author(s):  
Darrell O. Ricke ◽  
Robert W. Malone
Keyword(s):  
Amino Acid ◽  
T Cell ◽  
Amino Acid Residue ◽  
Antiviral Drug ◽  
Cell Vaccine ◽  
Variation Analysis ◽  
S Protein ◽  
Antibody Dependent Enhancement ◽  
T Effector Cells ◽  
Reduce Risk

Background: In 80% of patients, COVID-19 presents as mild disease1,2. 20% of cases develop severe (13%) or critical (6%) illness. More severe forms of COVID-19 present as clinical severe acute respiratory syndrome, but include a T-predominant lymphopenia3, high circulating levels of proinflammatory cytokines and chemokines, accumulation of neutrophils and macrophages in lungs, and immune dysregulation including immunosuppression4. Methods: All major SARS-CoV-2 proteins were characterized using an amino acid residue variation analysis method. Results predict that most SARS-CoV-2 proteins are evolutionary constrained, with the exception of the spike (S) protein extended outer surface. Results were interpreted based on known SARS-like coronavirus virology and pathophysiology, with a focus on medical countermeasure development implications. Findings: Non-neutralizing antibodies to variable S domains may enable an alternative infection pathway via Fc receptor-mediated uptake. This may be a gating event for the immune response dysregulation observed in more severe COVID-19 disease. Prior studies involving vaccine candidates for FCoV5,6 SARS-CoV-17-10 and Middle East Respiratory Syndrome coronavirus (MERS-CoV) 11 demonstrate vaccination-induced antibody-dependent enhancement of disease (ADE), including infection of phagocytic antigen presenting cells (APC). T effector cells are believed to play an important role in controlling coronavirus infection; pan-T depletion is present in severe COVID-19 disease3 and may be accelerated by APC infection. Sequence and structural conservation of S motifs suggests that SARS and MERS vaccine ADE risks may foreshadow SARS-CoV-2 S-based vaccine risks. Autophagy inhibitors may reduce APC infection and T-cell depletion12 13. Amino acid residue variation analysis identifies multiple constrained domains suitable as T cell vaccine targets. Evolutionary constraints on proven antiviral drug targets present in SARS-CoV-1 and SARS-CoV-2 may reduce risk of developing antiviral drug escape mutants. Interpretation: Safety testing of COVID-19 S protein-based B cell vaccines in animal models is strongly encouraged prior to clinical trials to reduce risk of ADE upon virus exposure.

scholarly journals Kinetic characterization of yeast alcohol dehydrogenases. Amino acid residue 294 and substrate specificity.

1987 ◽  
Vol 262 (8) ◽  
pp. 3754-3761
Author(s):  
A.J. Ganzhorn ◽  
D.W. Green ◽  
A.D. Hershey ◽  
R.M. Gould ◽  
B.V. Plapp
Keyword(s):  
Amino Acid ◽  
Substrate Specificity ◽  
Amino Acid Residue ◽  
Kinetic Characterization ◽  
Alcohol Dehydrogenases

scholarly journals Amino Acid Residue at the 165th Position Tunes Eyfp Chromophore Maturation. A Structure-Based Design

2021 ◽  
Author(s):  
Nadya V. Pletneva ◽  
Eugene G. Maksimov ◽  
Elena A. Protasova ◽  
Anastasia V. Mamontova ◽  
Tatiana R. Simonyan ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Residue

scholarly journals The Functional Consequences of the Novel Ribosomal Pausing Site in SARS-CoV-2 Spike Glycoprotein RNA

2021 ◽  
Vol 22 (12) ◽  
pp. 6490
Author(s):  
Olga A. Postnikova ◽  
Sheetal Uppal ◽  
Weiliang Huang ◽  
Maureen A. Kane ◽  
Rafael Villasmil ◽  
...  
Keyword(s):  
Amino Acid ◽  
Insertion Sequence ◽  
Experimental Studies ◽  
Spike Protein ◽  
Spike Glycoprotein ◽  
Furin Cleavage ◽  
New Host ◽  
S Protein ◽  
Furin Cleavage Site ◽  
Ribosome Pausing

The SARS-CoV-2 Spike glycoprotein (S protein) acquired a unique new 4 amino acid -PRRA- insertion sequence at amino acid residues (aa) 681–684 that forms a new furin cleavage site in S protein as well as several new glycosylation sites. We studied various statistical properties of the -PRRA- insertion at the RNA level (CCUCGGCGGGCA). The nucleotide composition and codon usage of this sequence are different from the rest of the SARS-CoV-2 genome. One of such features is two tandem CGG codons, although the CGG codon is the rarest codon in the SARS-CoV-2 genome. This suggests that the insertion sequence could cause ribosome pausing as the result of these rare codons. Due to population variants, the Nextstrain divergence measure of the CCU codon is extremely large. We cannot exclude that this divergence might affect host immune responses/effectiveness of SARS-CoV-2 vaccines, possibilities awaiting further investigation. Our experimental studies show that the expression level of original RNA sequence “wildtype” spike protein is much lower than for codon-optimized spike protein in all studied cell lines. Interestingly, the original spike sequence produces a higher titer of pseudoviral particles and a higher level of infection. Further mutagenesis experiments suggest that this dual-effect insert, comprised of a combination of overlapping translation pausing and furin sites, has allowed SARS-CoV-2 to infect its new host (human) more readily. This underlines the importance of ribosome pausing to allow efficient regulation of protein expression and also of cotranslational subdomain folding.

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