scholarly journals Identification of Amino Acid Substitutions with Compensational Effects in the Attachment Protein of Canine Distemper Virus

2014 ◽  
Vol 88 (14) ◽  
pp. 8057-8064 ◽  
Author(s):  
Ursula Sattler ◽  
Mojtaba Khosravi ◽  
Mislay Avila ◽  
Paola Pilo ◽  
Johannes P. Langedijk ◽  
...  

ABSTRACTThe hemagglutinin (H) gene of canine distemper virus (CDV) encodes the receptor-binding protein. This protein, together with the fusion (F) protein, is pivotal for infectivity since it contributes to the fusion of the viral envelope with the host cell membrane. Of the two receptors currently known for CDV (nectin-4 and the signaling lymphocyte activation molecule [SLAM]), SLAM is considered the most relevant for host susceptibility. To investigate how evolution might have impacted the host-CDV interaction, we examined the functional properties of a series of missense single nucleotide polymorphisms (SNPs) naturally accumulating within the H-gene sequences during the transition between two distinct but related strains. The two strains, a wild-type strain and a consensus strain, were part of a single continental outbreak in European wildlife and occurred in distinct geographical areas 2 years apart. The deduced amino acid sequence of the two H genes differed at 5 residues. A panel of mutants carrying all the combinations of the SNPs was obtained by site-directed mutagenesis. The selected mutant, wild type, and consensus H proteins were functionally evaluated according to their surface expression, SLAM binding, fusion protein interaction, and cell fusion efficiencies. The results highlight that the most detrimental functional effects are associated with specific sets of SNPs. Strikingly, an efficient compensational system driven by additional SNPs appears to come into play, virtually neutralizing the negative functional effects. This system seems to contribute to the maintenance of the tightly regulated function of the H-gene-encoded attachment protein.IMPORTANCETo investigate how evolution might have impacted the host-canine distemper virus (CDV) interaction, we examined the functional properties of naturally occurring single nucleotide polymorphisms (SNPs) in the hemagglutinin gene of two related but distinct strains of CDV. The hemagglutinin gene encodes the attachment protein, which is pivotal for infection. Our results show that few SNPs have a relevant detrimental impact and they generally appear in specific combinations (molecular signatures). These drastic negative changes are neutralized by compensatory mutations, which contribute to maintenance of an overall constant bioactivity of the attachment protein. This compensational mechanism might reflect the reaction of the CDV machinery to the changes occurring in the virus following antigenic variations critical for virulence.

1999 ◽  
Vol 73 (3) ◽  
pp. 2263-2269 ◽  
Author(s):  
Pascal Cherpillod ◽  
Karin Beck ◽  
Andreas Zurbriggen ◽  
Riccardo Wittek

ABSTRACT The biological properties of wild-type A75/17 and cell culture-adapted Onderstepoort canine distemper virus differ markedly. To learn more about the molecular basis for these differences, we have isolated and sequenced the protein-coding regions of the attachment and fusion proteins of wild-type canine distemper virus strain A75/17. In the attachment protein, a total of 57 amino acid differences were observed between the Onderstepoort strain and strain A75/17, and these were distributed evenly over the entire protein. Interestingly, the attachment protein of strain A75/17 contained an extension of three amino acids at the C terminus. Expression studies showed that the attachment protein of strain A75/17 had a higher apparent molecular mass than the attachment protein of the Onderstepoort strain, in both the presence and absence of tunicamycin. In the fusion protein, 60 amino acid differences were observed between the two strains, of which 44 were clustered in the much smaller F2 portion of the molecule. Significantly, the AUG that has been proposed as a translation initiation codon in the Onderstepoort strain is an AUA codon in strain A75/17. Detailed mutation analyses showed that both the first and second AUGs of strain A75/17 are the major translation initiation sites of the fusion protein. Similar analyses demonstrated that, also in the Onderstepoort strain, the first two AUGs are the translation initiation codons which contribute most to the generation of precursor molecules yielding the mature form of the fusion protein.


Author(s):  
Oriana Kreutzfeld ◽  
Stephanie A. Rasmussen ◽  
Aarti A. Ramanathan ◽  
Patrick K. Tumwebaze ◽  
Oswald Byaruhanga ◽  
...  

Among novel compounds under recent investigation as potential new antimalarial drugs are three independently developed inhibitors of the Plasmodium falciparum P-type ATPase (PfATP4): KAE609 (cipargamin), PA92, and SJ733. We assessed ex vivo susceptibilities to these compounds of 374 fresh P. falciparum isolates collected in Tororo and Busia districts, Uganda from 2016-2019. Median IC 50 s were 65 nM for SJ733, 9.1 nM for PA92, and 0.5 nM for KAE609. Sequencing of pfatp4 for 218 of these isolates demonstrated many non-synonymous single nucleotide polymorphisms; the most frequent mutations were G1128R (69% of isolates mixed or mutant), Q1081K/R (68%), G223S (25%), N1045K (16%) and D1116G/N/Y (16%). The G223S mutation was associated with decreased susceptibility to SJ733, PA92 and KAE609. The D1116G/N/Y mutations were associated with decreased susceptibility to SJ733, and the presence of mutations at both codons 223 and 1116 was associated with decreased susceptibility to PA92 and SJ733. In all of these cases, absolute differences in susceptibilities of wild type (WT) and mutant parasites were modest. Analysis of clones separated from mixed field isolates consistently identified mutant clones as less susceptible than WT. Analysis of isolates from other sites demonstrated presence of the G223S and D1116G/N/Y mutations across Uganda. Our results indicate that malaria parasites circulating in Uganda have a number of polymorphisms in PfATP4 and that modestly decreased susceptibility to PfATP4 inhibitors is associated with some mutations now present in Ugandan parasites.


2013 ◽  
Vol 57 (11) ◽  
pp. 5658-5664 ◽  
Author(s):  
Soo-Jin Yang ◽  
Nagendra N. Mishra ◽  
Aileen Rubio ◽  
Arnold S. Bayer

ABSTRACTSingle nucleotide polymorphisms (SNPs) within themprFopen reading frame (ORF) have been commonly observed in daptomycin-resistant (DAPr)Staphylococcus aureusstrains. Such SNPs are usually associated with a gain-in-function phenotype, in terms of either increased synthesis or enhanced translocation (flipping) of lysyl-phosphatidylglycerol (L-PG). However, it is unclear if suchmprFSNPs are causal in DAPrstrains or are merely a biomarker for this phenotype. In this study, we used an isogenic set ofS. aureusstrains: (i) Newman, (ii) its isogenic ΔmprFmutant, and (iii) several intransplasmid complementation constructs, expressing either a wild-type or point-mutated form of themprFORF cloned from two isogenic DAP-susceptible (DAPs)-DAPrstrain pairs (616-701 and MRSA11/11-REF2145). Complementation of the ΔmprFstrain with singly point-mutatedmprFgenes (mprFS295LormprFT345A) revealed that (i) individual and distinct point mutations within themprFORF can recapitulate phenotypes observed in donor strains (i.e., changes in DAP MICs, positive surface charge, and cell membrane phospholipid profiles) and (ii) these gain-in-function SNPs (i.e., enhanced L-PG synthesis) likely promote reduced DAP binding toS. aureusby a charge repulsion mechanism. Thus, for these two DAPrstrains, the definedmprFSNPs appear to be causally related to this phenotype.


Author(s):  
Zahraa Isam ◽  
Rabab Omran ◽  
Ammad Hassan Mahmood

  Objective: The calcium-sensing receptor (CASR) is a G-protein-coupled receptor that is mainly expressed in the parathyroid and the kidneys where it regulates parathyroid hormone secretion and renal tubular calcium reabsorption. Inactivating and activating CASR gene due to mutations severally caused hypercalcemia or hypocalcemia disorders. The aim of the study was to investigate the risk factor of CASR rs1801725 (Ala986Ser) patients with renal disease.Method: The blood samples were collected from 100 patients and divided into two groups, each one containing 50 samples; chronic kidney disease and end-stage renal disease, who admitted Merjan Teaching Hospital in Babylon Province, Iraq, from February to July 2016. In addition, healthy persons as a control group (50 samples). Genotyping of CASR single-nucleotide polymorphisms (SNP) was performed using a polymerase chain reaction technique, followed by single-strand conformation polymorphism. Accordingly, these DNA polymorphisms were confirmed using DNA sequencing.Results: The conformational haplotypes of CASR, exon7 NCBI Primer3plus reference were obtained in three patterns, including two, three, and four bands, due to the presence SNPs within the studied region. These SNPs leads to change three amino acid residues of CASR, including amino acid substitutions were Ala 128→ Ser 128, Leu 155→Tye 155, and Leu 156→ Ser 156 that may affect or modified the tertiary structure of the receptor, subsequently the function like the affinity to calcium ion may be effected.Conclusion: These results suggest that the variants of CASR SNP, namely, rs1801725 might be involved in susceptibility to kidney stone disease.


2007 ◽  
Vol 05 (06) ◽  
pp. 1297-1318 ◽  
Author(s):  
CATHERINE L. WORTH ◽  
G. RICHARD J. BICKERTON ◽  
ADRIAN SCHREYER ◽  
JULIA R. FORMAN ◽  
TAMMY M. K. CHENG ◽  
...  

The prediction of the effects of nonsynonymous single nucleotide polymorphisms (nsSNPs) on function depends critically on exploiting all information available on the three-dimensional structures of proteins. We describe software and databases for the analysis of nsSNPs that allow a user to move from SNP to sequence to structure to function. In both structure prediction and the analysis of the effects of nsSNPs, we exploit information about protein evolution, in particular, that derived from investigations on the relation of sequence to structure gained from the study of amino acid substitutions in divergent evolution. The techniques developed in our laboratory have allowed fast and automated sequence-structure homology recognition to identify templates and to perform comparative modeling; as well as simple, robust, and generally applicable algorithms to assess the likely impact of amino acid substitutions on structure and interactions. We describe our strategy for approaching the relationship between SNPs and disease, and the results of benchmarking our approach — human proteins of known structure and recognized mutation.


2017 ◽  
Vol 145 (12) ◽  
pp. 2618-2625
Author(s):  
L. JIN ◽  
S. XU ◽  
P. A. C. MAPLE ◽  
W. XU ◽  
K. E. BROWN

SummaryVaricella–zoster virus (VZV) infection (chickenpox) results in latency and subsequent reactivation manifests as shingles. Effective attenuated vaccines (vOka) are available for prevention of both illnesses. In this study, an amplicon-based sequencing method capable of differentiating between VZV wild-type (wt) strains and vOka vaccine is described. A total of 44 vesicular fluid specimens collected from 43 patients (16 from China and 27 from the UK) with either chickenpox or shingles were investigated, of which 10 had received previous vaccination. Four sets of polymerase chain reactions were set up simultaneously with primers amplifying regions encompassing four single nucleotide polymorphisms (SNPs), ‘69349-106262-107252-108111’. Nucleotide sequences were generated by Sanger sequencing. All samples except one had a wt SNP profile of ‘A-T-T-T’. The sample collected from a patient who received vaccine 7–10 days ago, along with VZV vaccine preparations, Zostavax and Baike-varicella gave a SNP profile ‘G-C-C-C’. The results show that this method can distinguish vaccine-derived virus from wt viruses from main four clades, (clades 1–4) and should be of utility worldwide.


2021 ◽  
Vol 12 ◽  
Author(s):  
Marie-Christine Bartens ◽  
Amanda J. Gibson ◽  
Graham J. Etherington ◽  
Federica Di Palma ◽  
Angela Holder ◽  
...  

Recent evidence suggests that several cattle breeds may be more resistant to infection with the zoonotic pathogen Mycobacterium bovis. Our data presented here suggests that the response to mycobacterial antigens varies in macrophages generated from Brown Swiss (BS) and Holstein Friesian (HF) cattle, two breeds belonging to the Bos taurus family. Whole genome sequencing of the Brown Swiss genome identified several potential candidate genes, in particular Toll-like Receptor-2 (TLR2), a pattern recognition receptor (PRR) that has previously been described to be involved in mycobacterial recognition. Further investigation revealed single nucleotide polymorphisms (SNP) in TLR2 that were identified between DNA isolated from cells of BS and HF cows. Interestingly, one specific SNP, H326Q, showed a different genotype frequency in two cattle subspecies, Bos (B.) taurus and Bos indicus. Cloning of the TLR2 gene and subsequent gene-reporter and chemokine assays revealed that this SNP, present in BS and Bos indicus breeds, resulted in a significantly higher response to mycobacterial antigens as well as tri-acylated lipopeptide ligands in general. Comparing wild-type and H326Q containing TLR2 responses, wild-type bovine TLR2 response showed clear, diminished mycobacterial antigen responses compared to human TLR2, however bovine TLR2 responses containing H326Q were found to be partially recovered compared to human TLR2. The creation of human:bovine TLR2 chimeras increased the response to mycobacterial antigens compared to the full-length bovine TLR2, but significantly reduced the response compared to the full-length human TLR2. Thus, our data, not only present evidence that TLR2 is a major PRR in the mammalian species-specific response to mycobacterial antigens, but furthermore, that there are clear differences between the response seen in different cattle breeds, which may contribute to their enhanced or reduced susceptibility to mycobacterial infection.


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