Comparative Analyses of ACE2 Receptor Binding Corona Viruses that Cause Mild versus Severe Acute Respiratory Syndrome in Humans

Receptor Binding ◽

Metal Binding ◽

Protein Sequence ◽

Active Sites ◽

X Ray ◽

Glycosylation Sites ◽

Spike Proteins

Aim: To analyze the spike proteins and Replication-Transcription Complexes (RTCs) of the Mild and Severe Acute Respiratory Syndrome (SARS) and SARS-related coronaviruses (CoVs) to find out the similarities and differences between them, as both of groups bind to angiotensin-converting enzyme 2 (ACE2) receptor for human cell entry. Study Design: Bioinformatics, Biochemical, Site-Directed Mutagenesis (SDM), X-ray crystallographic, cryo-Electron microscopic (cryo-EM) and Mass Spectrometric (MS) data were analyzed. Methodology: The protein sequence data for spike proteins and the proteins of the RTCs, viz. the RNA- dependent RNA polymerases (RdRps), primases and the nonstructural protein 7 (NSP7) were obtained from PUBMED and SWISS-PROT databases. The advanced version of Clustal Omega was used for protein sequence analysis. Along with the conserved motifs identified by the bioinformatics analysis, the data already available by biochemical and SDM experiments and X-ray crystallographic and cryo-EM studies on these proteins were used to confirm the possible amino acids involved in ACE2 receptor binding and active sites of the RTCs. For identification of probable N-linked and O-linked glycosylation sites, NetNGlyc 1.0 and NetOGlyc 4.0 tools of Technical University of Denmark were used. ExPASy tool was used for pI analysis. Results: The spike protein of human CoV (HCoV)-NL63 is ~90 amino acids longer than the spike proteins of SARS and SARS-related CoVs. The additions are mostly found in the N-terminal regions and few insertions are also found in the crucial receptor binding domain (RBD). The SARS and SARS-related CoVs and HCoV-NL63 showed several conserved residues, motifs and large peptide regions. The most important aspect between the recent pandemic causing SARS-CoV-2 and HCoV-NL63 is a unique but different tetrapeptide insertions very close to the S1/S2 cleavage region, i.e., -PRRA- and -IPVR-, respectively. The next cleavage point S2’ and the transmembrane domains are conserved between the two groups. The RdRps are highly conserved between the two groups. The catalytic regions, catalytic amino acids and the NTP selection tripeptide regions are completely conserved between SARS-CoVs and HCoV-NL63. However, one of the metal binding sites, viz. the universal –GDD- reported in all RdRps is aligning with– KDG- in the RdRp of HCoV-NL63. The other metal binding site, viz. –SDD- is completely conserved in both the groups. The NiRAN domains of the RdRps differed from the possible catalytic amino acid and NTP selection tripeptide regions. The primases (NSP8) and the NSP7 subunits of the RTC are highly conserved in both the groups. The NSP8 and NSP7 subunits exhibit closer similarities between the MERS-CoV and HCoV-NL63. Unlike other SARS and SARS-related CoVs, the HCoV-NL63 possesses only a single accessory protein. Interestingly, a large number of amino acids are replaced with Ns in the spike proteins (which is also reflected in the number of N-linked glycosylation sites in it) as well as in the RTC. Conclusions: Detailed analysis revealed several unique features in the HCoV-NL63 pathogen. As all the pandemic strains like SARS-CoV-1, SARS-CoV-2 and the milder HCoV-NL63 strain, use the same ACE2 receptor for entry into human cells, the frequent infection of humans by HCoV-NL63, especially in children, suggests that there is an ample opportunity for highly pathogenic variants to evolve in the future.

An Overview of the Proofreading Functions in Bacteria and in Severe Acute Respiratory Syndrome-Coronaviruses

International Journal of Biochemistry Research & Review ◽

10.9734/ijbcrr/2021/v30i330258 ◽

2021 ◽

pp. 33-62

Author(s):

Peramachi Palanivelu

Keyword(s):

Amino Acids ◽

Structure Function ◽

Active Site ◽

Active Sites ◽

Dna Polymerases ◽

Proton Acceptor ◽

Conserved Motifs ◽

Bacterial Dna ◽

X Ray

Aim: To understand the structure-function relationship of the proofreading (PR) functions in eubacteria and viruses with special reference to Severe Acute Respiratory Syndrome-Coronaviruses (SARS-CoVs) and propose a plausible mechanism of action for PR exonucleases of SARS-CoVs. Study Design: Bioinformatics, biochemical, site-directed mutagenesis (SDM), X-ray crystallographic data were used to study the structure-function relationships of the PR exonucleases from bacteria and CoVs. Methodology: The protein sequences of the PR exonucleases of various DNA polymerases, and RNA polymerases of SARS, SARS-related and human CoVs (HCoVs) were obtained from PUBMED and SWISS-PROT databases. The advanced version of Clustal Omega was used for protein sequence analysis. Along with the conserved motifs identified by the bioinformatics analysis, the data already available by biochemical, SDM experiments and X-ray crystallographic analysis on these enzymes were used to arrive at the possible active amino acids in the PR exonucleases of these crucial enzymes. Results: A complete analysis of the active sites of the PR exonucleases from various bacteria and CoVs were done. The multiple sequence alignment (MSA) analysis showed many conserved amino acids, small and large peptide regions among them. Based on the conserved motifs, the PR exonucleases are found to fit broadly into two superfamilies, viz. DEDD and polymerase-histidinol phosphatase (PHP) superfamilies. The bacterial DNA polymerases I and II, RNase D, RNase T and ε-subunit of DNA polymerases III belong to the DEDD superfamily. The PR enzymes from SARS, SARS-related CoVs and other HCoVs also essentially belong to the DEDD superfamily. The DEDD superfamily either uses an invariant Tyr or a His as proton acceptor during catalysis. Depending on the proton acceptor, they are further classified into DEDHD and DEDYD subfamilies. RNase T, ε-subunit of DNA polymerases III and the SARS, SARS-related CoVs and other HCoVs belong to DEDHD subfamily. However, the SARS, SARS-related CoVs and other HCoVs showed additional zinc finger motifs (ZFMs) in their active sites. DNA polymerases I, II and RNase D belong to DEDYD subfamily. The bacterial DNA polymerases X, YcdX phosphoesterases and the co-editing exonuclease of DNA polymerases III belong to the PHP superfamily. Based on the MSA, X-ray crystallographic analyses and SDM experiments, the proposed active-site proton acceptor is Tyr/His in DEDDY/H subfamilies and His in PHP superfamily of PR exonucleases. Conclusions: Based on the similarities of active site amino acids/motifs, it may be concluded that the DEDD and PHP superfamilies of PR exonucleases should have evolved from a common ancestor but diverged very long ago. The biochemical properties of these enzymes, including the four conserved acidic amino acid residues in the catalytic core, suggest that the CoVs might have acquired the exonuclease function, possibly from a prokaryote. However, the presence of two zinc fingers in the PR active site of the SARS, SARS-related CoVs and other HCoVs sets their PR exonucleases apart from other homologues.

Eukaryotic Multi-subunit DNA dependent RNA Polymerases: An Insight into Their Active Sites and Catalytic Mechanism

International Journal of Biochemistry Research & Review ◽

10.9734/ijbcrr/2019/v26i330097 ◽

2019 ◽

pp. 1-60

Author(s):

Peramachi Palanivelu

Keyword(s):

Amino Acids ◽

Metal Binding ◽

Active Sites ◽

Dna Polymerases ◽

Rna Polymerases ◽

Site Directed Mutagenesis ◽

Binding Motif ◽

Conserved Motifs ◽

X Ray ◽

Eukaryotic Organisms

Aim: To analyze the most complex multi-subunit (MSU) DNA dependent RNA polymerases (RNAPs) of eukaryotic organisms and find out conserved motifs, metal binding sites and catalytic regions and propose a plausible mechanism of action for these complex eukaryotic MSU RNAPs, using yeast (Saccharomyces cerevisiae) RNAP II, as a model enzyme. Study Design: Bioinformatics, Biochemical, Site-directed mutagenesis and X-ray crystallographic data were analyzed. Place and Duration of Study: School of Biotechnology, Madurai Kamaraj University, Madurai, India, between 2007- 2013. Methodology: Bioinformatics, Biochemical, Site-directed mutagenesis (SDM) and X-ray crystallographic data of the enzyme were analyzed. The advanced version of Clustal Omega was used for protein sequence analysis of the MSU DNA dependent RNAPs from various eukaryotic sources. Along with the conserved motifs identified by the bioinformatics analysis, the data already available by biochemical and SDM experiments and X-ray crystallographic analysis of these enzymes were used to confirm the possible amino acids involved in the active sites and catalysis. Results: Multiple sequence alignment (MSA) of RNAPs from different eukaryotic organisms showed a large number of highly conserved motifs among them. Possible catalytic regions in the catalytic subunits of the yeast Rpb2 (= β in eubacteria) and Rpb1 (= β’ in eubacteria) consist of an absolutely conserved amino acid R, in contrast to a K that was reported for DNA polymerases and single subunit (SSU) RNAPs. However, the invariant ‘gatekeeper/DNA template binding’ YG pair that was reported in all SSU RNAPs, prokaryotic MSU RNAPs and DNA polymerases is also highly conserved in eukaryotic Rpb2 initiation subunits, but unusually a KG pair is found in higher eukaryotes including the human RNAPs. Like the eubacterial initiation subunits of MSU RNAPs, the eukaryotic initiation subunits, viz. Rpb2, exhibit very similar active site and catalytic regions but slightly different distance conservations between the template binding YG/KG pair and the catalytic R. In the eukaryotic initiation subunits, the proposed catalytic R is placed at the -9th position from the YG/KG pair and an invariant R is placed at -5 which are implicated to play a role in nucleoside triphosphate (NTP) selection as reported for SSU RNAPs (viral family) and DNA polymerases. Similarly, the eukaryotic elongation subunits (Rpb1) are also found to be very much homologous to the elongation subunits (β’) of prokaryotes. Interestingly, the catalytic regions are highly conserved, and the metal binding sites are absolutely conserved as in prokaryotic MSU RNAPs. In eukaryotes, the template binding YG pair is replaced with an FG pair. Another interesting observation is, similar to the prokaryotic β’ subunits, in the eukaryotic Rpb1 elongation subunits also, the proposed catalytic R is placed double the distance, i.e., -18 amino acids downstream from the FG pair unlike in the SSU RNAPs and DNA polymerases where the distance is only -8 amino acids downstream from the YG pair. Thus, the completely conserved FG pair, catalytic R with an invariant R, at -6th position are proposed to play a crucial role in template binding, NTP selection and polymerization reactions in the elongation subunits of eukaryotic MSU RNAPs. Moreover, the Zn binding motif with the three completely conserved Cs is also highly conserved in the eukaryotic elongation subunits. Another important difference is that the catalytic region is placed very close to the N-terminal region in eukaryotes. Conclusions: Unlike reported for the DNA polymerases and SSU RNA polymerases, the of eukaryotic MSU RNAPs use an R as the catalytic amino acid and exhibit a different distance conservation in the initiation and elongation subunits. An invariant Zn2+ binding motif found in the Rpb1 elongation subunits is proposed to participate in proof-reading function. Differences in the active sites of bacterial and human RNA polymerases may pave the way for the design of new and effective drugs for many bacterial infections, including the multidrug resistant strains which are a global crisis at present.

Analyses of the Spike Proteins of Severe Acute Respiratory Syndrome-Related Coronaviruses

Microbiology Research Journal International ◽

10.9734/mrji/2020/v30i830249 ◽

2020 ◽

pp. 32-50

Author(s):

Peramachi Palanivelu

Keyword(s):

Sequence Analysis ◽

Receptor Binding ◽

Spike Protein ◽

Conserved Motifs ◽

Loop Region ◽

Palm Civet ◽

Clustal Omega ◽

Spike Proteins

Aim: To analyze spike proteins of Severe Acute Respiratory Syndrome (SARS)-related coronaviruses (CoVs) for their conserved motifs, Receptor-Binding Domain (RBD), Receptor Binding Motif (RBM) of SARS-CoV (CoV-1), SARS-CoV-2, Middle East Respiratory Syndrome (MERS)-CoV and their relationship to the bat, pangolin and palm civet-CoVs as possible intermediate hosts. Study Design: Multiple sequence analysis (MSA) of spike proteins of different SARS-CoVs were studied using Clustal Omega and ExPASy tools. Methodology: Bioinformatics, SDM and X-ray crystallographic data of the spike proteins from different CoVs including the current epidemic causing SARS-CoV-2 were analyzed. The advanced version of Clustal Omega was used for protein sequence analysis of different spike proteins from various CoVs and ExPASy tool was used for pI analysis. Results: Spike proteins in coronaviruses play important roles in mediating receptor binding, membrane fusion, and viral entry into human cells. Furthermore, nowadays all the vaccine development programmes are mainly focused on the SARS-CoV-2 spike protein only, as it plays the crucial, first step in the infection process. Therefore, the spike proteins of the SARS-related coronaviruses, the main determinant of coronavirus host specificity, are analyzed for their conserved motifs, RBD, RBM, etc. The recent epidemic causing strain, SARS-CoV-2, showed 2 dipeptide deletions and 4 peptide insertions ranging from tetra- to hepta-peptides in its spike protein as compared to its predecessor CoV-1. Most of the insertions are also found in the bat and pangolin CoVs except one unique tetrapeptide. The RBM region shows that the bats, pangolins and CoV-2 exhibit very similar to identical sequences. The overall analyses show that the latest SARS-CoV-2 is related to bats and more to pangolin-CoVs suggesting that the pangolins could be possibly the intermediate host. On the other hand, it is found that palm civet RBM sequences are highly related to CoV-1 and not CoV-2. Possibly the novel CoV-2 would have taken three insertions from bats and/or pangolins and the fourth insertion –PRRA- which is unique to SARS-CoV-2 is critically placed just in the S1/S2 cleavage region. The recently discovered G614 mutation (D614→G) in CoV-2, the most prevalent form in the global pandemic now, is found near the RBD towards the C-terminal. Placement of the unique tetrapeptide in the S1/S2 loop region and replacement with more positive charges on the spike protein which resulted in marked increase in the basicity of the SARS-CoV-2 spike protein may, possibly result in significant effects on the structure and function of the protein, possibly leading to rapid transmission. Conclusions: RBD and RBM regions of the spike proteins of SARS-CoV-1 and palm civet show very close identity to each other whereas the SARS-CoV-2, pangolin- and bat-CoVs exhibit very close identities in their RBD and RBM regions. The two crucial modifications in the spike protein of SARS-CoV-2, viz. a marked increase in the basicity of the protein and the insertion of a dibasic tetrapeptide (–PRRA-) at the critical S1/S2 cleavage point possibly make it to bind to the ACE2 receptor with higher affinity and get it cleaved by the host proteases more efficiently with subsequent effective internalization of the viral genome.

Analyses of Homing Endonucleases and Mechanism of Action of CRISPR-Cas9 HNH Endonucleases

International Journal of Biochemistry Research & Review ◽

10.9734/ijbcrr/2020/v29i630192 ◽

2020 ◽

pp. 1-25

Author(s):

Peramachi Palanivelu

Keyword(s):

Amino Acids ◽

Mechanism Of Action ◽

Metal Binding ◽

Binding Sites ◽

Proton Acceptor ◽

Homing Endonucleases ◽

Multiple Sequence ◽

Conserved Motifs ◽

X Ray ◽

Metal Binding Sites

Aim: To analyze different HNH endonucleases from various sources including the HNH endonuclease regions of CRISPR-Cas9 proteins for their conserved motifs, metal-binding sites and catalytic amino acids and propose a plausible mechanism of action for HNH endonucleases, using CRISPR-Cas9 as the model enzyme. Study Design: Multiple sequence analysis (MSA) of homing endonucleases including the CRISPR-Cas9 using Clustal Omega was studied. Other biochemical, Site-directed mutagenesis (SDM) and X-ray crystallographic data were also analyzed. Place and Duration of Study: School of Biotechnology, Madurai Kamaraj University, Madurai, India, between 2007 and 2013. Methodology: Bioinformatics, Biochemical, SDM and X-ray crystallographic data of the HNH endonucleases from different organisms including CRISPR-Cas9 enzymes were analyzed. The advanced version of Clustal Omega was used for protein sequence analysis of different HNH endonucleases from various sources. The conserved motifs identified by the bioinformatics analysis were analyzed further with the data already available from biochemical and SDM and X-ray crystallographic analyses of this group of enzymes and to confirm the possible amino acids involved in the active sites and catalysis. Results: Different types of homing endonucleases from various sources including the HNH endonuclease regions of CRISPR-Cas9 enzymes exhibit different catalytic regions and metal-binding sites. However, the catalytic amino acid, i.e., the proton acceptor histidine (His), is completely conserved in all homing endonucleases analyzed. From these data, a plausible mechanism of action for HNH endonucleases, using CRISPR-Cas9 from Streptococcus pyogenes, as the model enzyme is proposed. Furthermore, multiple sequence alignment (MSA) of various homing endonucleases from different organisms showed many highly conserved motifs also among them. However, some of the HNH endonucleases showed consensus only around the active site regions. Possible catalytic amino acids identified among them belong to either -DH---N or -HH--N types. There are at least two types of metal-binding sites and bind Mg2+ or Zn2+ or both. The CRISPR-Cas9 enzyme from S. pyogenes belongs to the -DH- based HNH endonucleases and possesses –DxD- type metal-binding site where it possibly binds to a Mg2+ ion. The other HNH enzymes possess one or two invariant Zn binding CxxC/ CxxxC motifs. Conclusions: The CRISPR-Cas9 enzymes are found to be -DH- type where the first D is likely to involve in metal-binding and the second invariant H acts as the proton acceptor and the N in –HNH- Cas9 confers specificity by interacting with the nucleotide near the catalytic region. In this communication, a metal-bound water molecule is shown as the nucleophile initiating catalysis. Homing endonucleases may be used as novel DNA binding and cleaving reagents for a variety of genome editing applications and Zinc finger nucleases have already found applications in genome editing.

Bioinformatics Analysis and Characteristics of US2 Protein Encoded by the Newly Identified US2 Gene of Duck Enteritis Virus

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.424-425.493 ◽

2012 ◽

Vol 424-425 ◽

pp. 493-497

Author(s):

Jie Gao ◽

An Chun Cheng ◽

Ming Shu Wang

Keyword(s):

Amino Acids ◽

Sequence Analysis ◽

Protein Sequence ◽

Bioinformatics Analysis ◽

Functional Study ◽

Tegument Proteins ◽

The Us ◽

New Type ◽

Enteritis Virus

In this article,we intend to provide readers with some bioinformation of DEV Us2 protein,for little information of this protein has been cited online.Us2 protein encoded by the DEV-US2 gene is one of the DEV tegument proteins. Like most members of the alphaherpesvirinae,the genes in the US region of its genome are well conserved,which means that both the major DEV protein Us2 and alphaherpesvirinae protein Us2 possess the similar functions.Us2 protein sequence analysis indicates that the protein possesses typical characteristics of tegument protein.The precursor Us2 consists of 239 amino acids and exhibits a molecular mass of 34 kDa. In conclusion,all the datas and consequences will provide a basis for further functional study of the DEV-Us2 protein and provide necessary datas for the new type clinical diagnosis of DEV and the development of new DEV vaccine.

Possible Transmission Flow of SARS-CoV-2 Based on ACE2 Features

Molecules ◽

10.3390/molecules25245906 ◽

2020 ◽

Vol 25 (24) ◽

pp. 5906

Author(s):

Sk. Sarif Hassan ◽

Shinjini Ghosh ◽

Diksha Attrish ◽

Pabitra Pal Choudhury ◽

Alaa A. A. Aljabali ◽

...

Keyword(s):

Amino Acids ◽

Angiotensin Converting Enzyme ◽

Receptor Binding ◽

Comprehensive Analysis ◽

Cellular Receptor ◽

Receptor Binding Domain ◽

Converting Enzyme ◽

Angiotensin Converting Enzyme 2 ◽

Protein Receptor

Angiotensin-converting enzyme 2 (ACE2) is the cellular receptor for the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) that is engendering the severe coronavirus disease 2019 (COVID-19) pandemic. The spike (S) protein receptor-binding domain (RBD) of SARS-CoV-2 binds to the three sub-domains viz. amino acids (aa) 22–42, aa 79–84, and aa 330–393 of ACE2 on human cells to initiate entry. It was reported earlier that the receptor utilization capacity of ACE2 proteins from different species, such as cats, chimpanzees, dogs, and cattle, are different. A comprehensive analysis of ACE2 receptors of nineteen species was carried out in this study, and the findings propose a possible SARS-CoV-2 transmission flow across these nineteen species.

A novel manual method for protein-sequence analysis

Biochemical Journal ◽

10.1042/bj1570077 ◽

1976 ◽

Vol 157 (1) ◽

pp. 77-85 ◽

Cited By ~ 33

Author(s):

J Y Chang ◽

E H Creaser

Keyword(s):

Amino Acids ◽

Sequence Analysis ◽

Protein Sequence ◽

Detection Sensitivity ◽

Phenyl Isothiocyanate ◽

Manual Method ◽

Terminal Residue ◽

A Chain

A novel manual method for protein-sequence analysis is described. Three peptides, the hexapeptide (Leu-TRP-Met-Arg-Phe-Ala), insulin A chain and glucagon were used to test this technique. Peptides (1 or 2 nmol) were hydrolysed with acid and their qualitative amino acid compositions were confirmed by reacting with 4-NN-dimethylaminoazobenzene-4'-sulphonylchloride and 4-NN-dimethylaminoazobenzene 4'-isothiocyanate. Sequence determination of 20-200 nmol of peptide was then performed by the combined use of phenyl isothiocyanate and 4-NN-dimethylaminoazobenzene 4'-isothiocyanate, a new procedure that is analogous to the dansyl-Edman method with the replacement of dansyl chloride by 4-NN-dimethylaminoazobenzene 4'-isothiocyanate as the N-terminal residue determination reagent. On t.l.c. this new N-terminal reagent gave brightly coloured 4-NN-dimethylaminoazobenzene-4-thiohydantoins of amino acids and showed the following advantages: (1) the detection sensitivity is in the pmol range; (2) u.v. observation is not required; (3) there is no destruction of acid-labile amino acids; (4) two-dimensional t.l.c. separation is adequate to identify 24 amino acids, except leucine and isoleucine (this pair of amino acids can be resolved by using 4-NN-dimethylaminoazobenzene-4'-sulphonyl chloride); (5) the determination of a new N-terminal residue (from coupling to t.l.c. identification) takes only 3 h; (6) the colour difference beteen isothiocyanate, thiocarbamoyl and thiohydantoin derivatives facilitates the identifications.

Comparative Investigations of the Sandfish’s β-Keratin (Reptilia: Scincidae: Scincus scincus). Part 1: Surface and Molecular Examinations

Journal of Biomimetics Biomaterials and Tissue Engineering ◽

10.4028/www.scientific.net/jbbte.15.1 ◽

2012 ◽

Vol 15 ◽

pp. 1-16 ◽

Cited By ~ 10

Author(s):

Konrad Staudt ◽

Friederike Petra Maria Saxe ◽

Heiko Schmied ◽

Raphael Soeur ◽

Wolfgang Böhme ◽

...

Keyword(s):

Amino Acids ◽

Chemical Composition ◽

Protein Sequence ◽

Micro Structure ◽

Low Friction ◽

Desert Sand ◽

Glycosylation Sites ◽

Keratin Proteins ◽

Reptilian Species ◽

Scincus Scincus

The Sandfish (Scincidae: Scincus Scincus) Is a Lizard Capable of Moving through Desert Sand in a Swimming-Like Fashion. the Epidermis of this Lizard Shows a High Resistance against Abrasion Together with a Low Friction to Sand as an Adaption to a Subterranean Life below the Desert’s Surface, Outperforming even Steel. the Low Friction Is Mainly Caused by Chemical Composition of the Scales, which Consist of Glycosylated β-Keratins. in this Study, the Friction, the Micro-Structure, the Glycosylation of the β-Keratin Proteins and β-Keratin Coding DNA of the Sandfish in Comparison to other Reptilian Species Was Investigated, Mainly with the Closely Related Berber Skink (Scincidae: Eumeces Schneideri) and another Sand Swimming Species, the Not Closer Related Shovel-Snouted Lizard (Lacertidae: Meroles Anchietae). Glycosylated β-Keratins of the Sandfish, Visualized with Different Lectins Resulted in O-Linked Glycans through PNA Employed as Carbohydrate Marker. Furthermore, the Glycosylation of β-Keratins in Various Squamatean Species Was Investigated and All Species Tested Were Found Positive; however, it Seems Like both Sand Swimming Species Examined Have a much Stronger Glycosylation of their β-Keratins. in Order to Prove this Finding through a Genetic Foundation, DNA of a β-Keratin Coding Gene of the Sandfish Was Sequenced and Compared with a Homologue Gene of Eumeces Schneideri. by Comparison of the Protein Sequence, a Higher Abundance of O-Glycosylation Sites Was Found in the Sandfish (enabled through the Amino Acids Serine and Threonine), Giving Molecular Support for a Higher Glycosylation of the β-Keratins in this Species.

Possible transmission flow of SARS-CoV-2 based on ACE2 features

10.1101/2020.10.08.332452 ◽

2020 ◽

Author(s):

Sk. Sarif Hassan ◽

Shinjini Ghosh ◽

Diksha Attrish ◽

Pabitra Pal Choudhury ◽

Vladimir N. Uversky ◽

...

Keyword(s):

Amino Acids ◽

Angiotensin Converting Enzyme ◽

Receptor Binding ◽

Comprehensive Analysis ◽

Cellular Receptor ◽

Receptor Binding Domain ◽

Converting Enzyme ◽

Angiotensin Converting Enzyme 2 ◽

Protein Receptor

AbstractAngiotensin-converting enzyme 2 (ACE2) is the cellular receptor for the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) that is engendering the severe coronavirus disease 2019 (COVID-19) pandemic. The spike (S) protein receptor-binding domain (RBD) of SARS-CoV-2 binds to the three sub-domains viz. amino acids (aa) 22-42, aa 79-84, and aa 330-393 of ACE2 on human cells to initiate entry. It was reported earlier that the receptor utilization capacity of ACE2 proteins from different species, such as cats, chimpanzees, dogs, and cattle, are different. A comprehensive analysis of ACE2 receptors of nineteen species was carried out in this study, and the findings propose a possible SARS-CoV-2 transmission flow across these nineteen species.