Recent zoonotic spillover and tropism shift of a Canine Coronavirus is associated with relaxed selection and putative loss of function in NTD subdomain of spike protein.

A recent study reported the occurrence of Canine Coronavirus (CCoV) in nasopharyngeal swabs from a small number of patients hospitalized with pneumonia during a 2017-18 period in Sarawak, Malaysia. Because the genome sequence for one of these isolates is available, we conducted comparative evolutionary analyses of the spike gene of this strain (CCoV-HuPn-2018), with other available Alphacoronavirus 1 spike sequences. The most N-terminus subdomain (0-domain) of the CCoV-HuPn-2018 spike protein has sequence similarity to Transmissible Gastroenteritis Virus (TGEV) and CCoV2b strains, but not to other members of the type II Alphacoronaviruses (i.e., CCoV2a and Feline CoV2-FCoV2). This 0-domain in CCoV-HuPn-2018 has evidence for relaxed selection pressure, an increased rate of molecular evolution, and a number of unique amino acid substitutions relative to CCoV2b and TGEV sequences. A region of the 0-domain determined to be key to sialic acid binding and pathogenesis in TGEV had clear differences in amino acid sequences in CCoV-HuPn-2018 relative to both CCoV2b (enteric) and TGEV (enteric and respiratory). The 0-domain of CCoV-HuPn-2018 also had several sites inferred to be under positive diversifying selection, including sites within the signal peptide. Downstream of the 0-domain, FCoV2 shared sequence similarity to the CCoV2b and TGEV sequences, with analyses of this larger alignment identifying positively selected sites in the putative Receptor Binding Domain (RBD) and Connector Domain (CD). Recombination analyses strongly implicated a particular FCoV2 strain in the recombinant history of CCoV-HuPn-2018 with molecular divergence times estimated at around 60 years ago. We hypothesize that CCoV-HuPn-2018 had an enteric origin, but that it has lost that particular tropism, because of mutations in the sialic acid binding region of the spike 0-domain. As selection pressure on this region was reduced, the virus evolved a respiratory tropism, analogous to other Alphacoronavirus 1, such as Porcine Respiratory Coronavirus (PRCV), that have lost this region entirely. We also suggest that signals of positive selection in the signal peptide as well as other changes in the 0-domain of CCoV-HuPn-2018 could represent an adaptive role in this new host and that this could be in part due to the different spatial distribution of the N-linked glycan repertoire for this strain.

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Incorporation of Fluorescent Nonnatural Amino Acid into Sialic Acid-Binding Lectin for Fluorescence Detection of Ligand-Binding

Bulletin of the Chemical Society of Japan ◽

10.1246/bcsj.20120345 ◽

2013 ◽

Vol 86 (6) ◽

pp. 729-735 ◽

Cited By ~ 2

Author(s):

Yasutaka Ito ◽

Takahiro Hohsaka

Keyword(s):

Sialic Acid ◽

Amino Acid ◽

Ligand Binding ◽

Fluorescence Detection ◽

Sialic Acid Binding ◽

Nonnatural Amino Acid ◽

Binding Lectin

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mSiglec-E, a novel mouse CD33-related siglec (sialic acid-binding immunoglobulin-like lectin) that recruits Src homology 2 (SH2)-domain-containing protein tyrosine phosphatases SHP-1 and SHP-2

Biochemical Journal ◽

10.1042/bj3530483 ◽

2001 ◽

Vol 353 (3) ◽

pp. 483-492 ◽

Cited By ~ 12

Author(s):

Zhenbao YU ◽

Meryem MAOUI ◽

Liangtang WU ◽

Denis BANVILLE ◽

Shi-Hsiang SHEN

Keyword(s):

Sialic Acid ◽

Sequence Similarity ◽

Tyrosine Phosphatase ◽

Protein Tyrosine Phosphatases ◽

Sh2 Domain ◽

Immunoglobulin Superfamily ◽

Protein Tyrosine ◽

Src Homology 2 ◽

Sialic Acid Binding ◽

Src Homology

The sialic acid-binding immunoglobulin-like lectins (siglecs) represent a recently defined distinct subset of the immunoglobulin superfamily. By using the Src homology 2 (SH2)-domain-containing protein tyrosine phosphatase SHP-1 as bait in a yeast two-hybrid screen, we have identified a new member of the mouse siglec family, mSiglec-E. The mSiglec-E cDNA encodes a protein of 467 amino acids that contains three extracellular immunoglobulin-like domains, a transmembrane region and a cytoplasmic tail bearing two immunoreceptor tyrosine-based inhibitory motifs (ITIMs). mSiglec-E is highly expressed in mouse spleen, a tissue rich in leucocytes. The ITIMs of mSiglec-E can recruit SHP-1 and SHP-2, two inhibitory regulators of immunoreceptor signal transduction. This suggests that the function of mSiglec-E is probably an involvement in haematopoietic cells and the immune system as an inhibitory receptor. When expressed in COS-7 cells, mSiglec-E was able to mediate sialic acid-dependent binding to human red blood cells, suggesting that mSiglec-E may function through cell–cell interactions. In comparison with the known members of the siglec family, mSiglec-E exhibits a high degree of sequence similarity to both human siglec-7 and siglec-9. The gene encoding mSiglec-E is localized in the same chromosome as that encoding mouse CD33. Phylogenetic analysis reveals that neither mouse mSiglec-E nor CD33 shows a clear relationship with any human siglecs so far identified.

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Amino acid change 335 E to K affects the sialic-acid-binding and neuraminidase activities of Urabe AM9 mumps virus hemagglutinin–neuraminidase glycoprotein

Microbes and Infection ◽

10.1016/j.micinf.2006.11.011 ◽

2007 ◽

Vol 9 (2) ◽

pp. 234-240 ◽

Cited By ~ 12

Author(s):

Julio Reyes-Leyva ◽

Rocío Baños ◽

María Borraz-Argüello ◽

Gerardo Santos-López ◽

Nora Rosas ◽

...

Keyword(s):

Sialic Acid ◽

Amino Acid ◽

Amino Acid Change ◽

Mumps Virus ◽

Sialic Acid Binding

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Identification, characterization and leucocyte expression of Siglec-10, a novel human sialic acid-binding receptor

Biochemical Journal ◽

10.1042/bj3550489 ◽

2001 ◽

Vol 355 (2) ◽

pp. 489-497 ◽

Cited By ~ 41

Author(s):

James MUNDAY ◽

Sheena KERR ◽

Jian NI ◽

Ann L. CORNISH ◽

Jiquan Q. ZHANG ◽

...

Keyword(s):

Sialic Acid ◽

Innate Immune System ◽

Sequence Similarity ◽

Innate Immune ◽

Inhibitory Receptor ◽

Human Spleen ◽

Minor Population ◽

Sialic Acid Binding ◽

A Minor ◽

High Degree

Here we characterize Siglec-10 as a new member of the Siglec family of sialic acid-binding Ig-like lectins. A full-length cDNA was isolated from a human spleen library and the corresponding gene identified. Siglec-10 is predicted to contain five extracellular Ig-like domains and a cytoplasmic tail containing three putative tyrosine-based signalling motifs. Siglec-10 exhibited a high degree of sequence similarity to CD33-related Siglecs and mapped to the same region, on chromosome 19q13.3. The expressed protein was able to mediate sialic acid-dependent binding to human erythrocytes and soluble sialoglycoconjugates. Using specific antibodies, Siglec-10 was detected on subsets of human leucocytes including eosinophils, monocytes and a minor population of natural killer-like cells. The molecular properties and expression pattern suggest that Siglec-10 may function as an inhibitory receptor within the innate immune system.

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Abundant transmission of Corona Virus Nsp2 RNA Topoisomerse I120F Mutants with Concurrence D614G Spike Protein Mutation in Australia

10.31219/osf.io/qeku2 ◽

2021 ◽

Author(s):

ASIT KUMAR CHAKRABORTY

Keyword(s):

Amino Acid ◽

Topoisomerase I ◽

Sequence Similarity ◽

Virus Transmission ◽

Spike Protein ◽

Virus Protein ◽

Dna Topoisomerase ◽

Amino Acid Homology ◽

Protein Mutation ◽

Corona Virus

We previously predicted Nsp2 Corona virus protein as RNA topoisomerase through amino acid homology among Vibrio haemolytica DNA topoisomerase IA/IV as well as DNA primase, DNA gyrase and bi-subunit Trypanosoma brucei DNA topoisomerase IB. Many DNA topoisomerase I/III have RNA topoisomerase activity and such ubiquitous enzymes are conserved and involved in the regulation of replication and transcription. We have checked here mutational profile of Nsp2 RNA topoisomerase analyzing >10000 orf1a 4405 amino acid length Corona virus polyprotein. Mutant proteins were selected by BLAST search having 99.84% sequence similarity and 181-818aa portion Nsp2 protein (protein id. QIU82057) was analyzed using CLUSTAL Omega software. We found 26 different mutations where most changes were selected at Isoleucine and Alanine into Valine or Leucine into Phenylanaline pinpointing conserved nature of the Corona virus RNA topoisomerase. Major nonsense very abundant mutations were found at I120F (Isoleucine to Phenylalanine). Other important mutations were R27C, I198V, T85I, L410F, I559V and P583S. The I120F mutation was abundant in Australian isolates and its spread was seen in the Bangladesh and other countries like USA. We suggest that abundant I120F mutation of Nsp2 Topoisomerase may increase transmission of Corona virus by stabilizing RNA structure for efficient virus pakaging. Interestingly, such mutations were found in association of D614G mutation of Spike protein, known to >70% increase infectivity. On the contrary, all P583S Nsp2 mutants analyzed had no concurrence D614G spike protein mutation. Many silent mutations (5-7) were detected by genome wide analysis but no N501Y Spike protein mutation. This is first report that predicts a link of greater Corona virus transmission with Nsp2 protein I120F and spike protein D614G mutations.

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Amino acid sequence of sialic acid binding lectin from frog (Rana catesbeiana) eggs

Biochemistry ◽

10.1021/bi00382a018 ◽

1987 ◽

Vol 26 (8) ◽

pp. 2189-2194 ◽

Cited By ~ 48

Author(s):

Koiti Titani ◽

Koji Takio ◽

Manabu Kuwada ◽

Kazuo Nitta ◽

Fusao Sakakibara ◽

...

Keyword(s):

Sialic Acid ◽

Amino Acid ◽

Amino Acid Sequence ◽

Rana Catesbeiana ◽

Sialic Acid Binding ◽

Binding Lectin

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Chemical-modification studies of a unique sialic acid-binding lectin from the snail Achatina fulica. Involvement of tryptophan and histidine residues in biological activity

Biochemical Journal ◽

10.1042/bj2540195 ◽

1988 ◽

Vol 254 (1) ◽

pp. 195-202 ◽

Cited By ~ 24

Author(s):

S Basu ◽

C Mandal ◽

A K Allen

Keyword(s):

Biological Activity ◽

Sialic Acid ◽

Amino Acid ◽

Fluorescence Emission ◽

Amino Acid Residues ◽

Achatina Fulica ◽

Histidine Residues ◽

Sialic Acid Binding ◽

Arginine Residues ◽

Binding Lectin

A unique sialic acid-binding lectin, achatininH (ATNH) was purified in single step from the haemolymph of the snail Achatina fulica by affinity chromatography on sheep submaxillary-gland mucin coupled to Sepharose 4B. The homogeneity was checked by alkaline gel electrophoresis, immunodiffusion and immunoelectrophoresis. Amino acid analysis showed that the lectin has a fairly high content of acidic amino acid residues (22% of the total). About 1.3% of the residues are half-cystine. The glycoprotein contains 21% carbohydrate. The unusually high content of xylose (6%) and fucose (2.7%) in this snail lectin is quite interesting. The protein was subjected to various chemical modifications in order to detect the amino acid residues and carbohydrate residues present in its binding sites. Modification of tyrosine and arginine residues did not affect the binding activity of ATNH; however, modification of tryptophan and histidine residues led to a complete loss of its biological activity. A marked decrease in the fluorescence emission was found as the tryptophan residues of ATNH were modified. The c.d. data showed the presence of an identical type of conformation in the native and modified agglutinin. The modification of lysine and carboxy residues partially diminished the biological activity. The activity was completely lost after a beta-elimination reaction, indicating that the sugars are O-glycosidically linked to the glycoprotein's protein moiety. This result confirms that the carbohydrate moiety also plays an important role in the agglutination property of this lectin.

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