scholarly journals A Single Amino Acid of NIaPro of Papaya ringspot virus Determines Host Specificity for Infection of Papaya

2008 ◽  
Vol 21 (8) ◽  
pp. 1046-1057 ◽  
Author(s):  
Kuan-Chun Chen ◽  
Chu-Hui Chiang ◽  
Joseph A. J. Raja ◽  
Fang-Lin Liu ◽  
Chun-Hsi Tai ◽  
...  
Keyword(s):  
Amino Acid ◽  
Host Specificity ◽  
Three Dimensional ◽  
Genomic Region ◽  
Terminal Region ◽  
Ringspot Virus ◽  
Single Amino Acid ◽  
Papaya Ringspot Virus ◽  
Recombinant Viruses ◽  
Tropical Areas

Most strains of Papaya ringspot virus (PRSV) belong to type W, causing severe loss on cucurbits worldwide, or type P, devastating papaya in tropical areas. While the host range of PRSV W is limited to plants of the families Chenopodiaceae and Cucuribitaceae, PRSV P, in addition, infects plants of the family Caricaceae (papaya family). To investigate one or more viral genetic determinants for papaya infection, recombinant viruses were constructed between PRSV P-YK and PRSV W-CI. Host reactions to recombinant viruses indicated that the viral genomic region covering the C-terminal region (142 residues) of NIaVPg, full NIaPro, and N-terminal region (18 residues) of NIb, is critical for papaya infection. Sequence analysis of this region revealed residue variations at position 176 of NIaVPg and positions 27 and 205 of NIaPro between type P and W viruses. Host reactions to the constructed mutants indicated that the amino acid Lys27 of NIaPro determines the host-specificity of PRSV for papaya infection. Predicted three-dimensional structures of NIaPros of parental viruses suggested that Lys27 does not affect the protease activity of NIaPro. Recovery of the infected plants from certain papaya-infecting mutants implied involvement of other viral factors for enhancing virulence and adaptation of PRSV on papaya.

scholarly journals Diversity of Papaya ringspot virus Isolates in Puerto Rico

HortScience ◽  
2016 ◽  
Vol 51 (4) ◽  
pp. 362-369 ◽  
Author(s):  
Cristina Zambrana-Echevarría ◽  
Lorriane De Jesús-Kim ◽  
Rocio Márquez-Karry ◽  
Dimuth Siritunga ◽  
David Jenkins
Keyword(s):  
United States ◽  
Puerto Rico ◽  
Amino Acid ◽  
Coat Protein ◽  
Puerto Rican ◽  
The United States ◽  
Terminal Region ◽  
Ringspot Virus ◽  
Papaya Ringspot Virus ◽  
Amino Terminal

Papaya ringspot virus (PRSV) devastates papaya production worldwide. In Puerto Rico, papaya fields can be completely infected with PRSV within a year of planting. Information about the diversity of the Puerto Rican PRSV (PR-PRSV) population is relevant to establish a control strategy in the island. The coat protein gene (cp) of PRSV was sequenced from 62 isolates from different regions in Puerto Rico. The viral population of PRSV in Puerto Rico has 4% nucleotide and 5% amino acid diversity. Analysis of the coat protein (CP) amino acid sequence showed a variable amino terminal (N-terminal) region with a conserved aphid transmission motif and a variable EK repeat region. The core and carboxyl terminal (C-terminal) region were conserved. In the phylogenetic analysis, Puerto Rican isolates grouped independently of their geographical origin, with the exception of southern isolates that formed two separate subgroups and were the most divergent. Sequences of the cp from the Puerto Rican isolates, when compared with sequences from other countries, showed least genetic distance with isolates from the United States and Australia, followed by other American and Caribbean isolates. The U.S. and Australian isolates are sister taxa to the Puerto Rican isolates in the phylogenetic tree. This suggests that PRSV from Puerto Rico and the isolates from the United States and Australia have a common origin thought to be from a Mexican population.

scholarly journals C-Terminal Region of STAT-1α Is Not Necessary for Its Ubiquitination and Degradation Caused by Mumps Virus V Protein

2002 ◽  
Vol 76 (24) ◽  
pp. 12683-12690 ◽  
Author(s):  
Noriko Yokosawa ◽  
Shin-ichi Yokota ◽  
Toru Kubota ◽  
Nobuhiro Fujii
Keyword(s):  
Amino Acid ◽  
Transcriptional Activation ◽  
Tandem Repeats ◽  
Mumps Virus ◽  
Terminal Region ◽  
Single Amino Acid ◽  
Luciferase Reporter ◽  
Enhancer Element ◽  
V Protein ◽  
Gene Assay

ABSTRACT Constitutive levels of production of STAT-1 were reduced by 10 h postinfection (p.i.) and significantly lost by 24 h p.i. in FL cells acutely infected with mumps virus (MuV). This result was consistent with that observed in previous studies and experiments with cells persistently infected with MuV (FLMT cells). There was a marked decrease in the amount of STAT-1 in cells expressing MuV accessory protein V (MuV-V). Furthermore, single amino acid substitutions in the Cys-rich region of V protein (Vc189a, Vc207a, and Vc214a) showed that each cysteine residue plays an important role in the decrease in STAT-1 production, but substitution of a histidine residue at amino acid position 203 had no effect. These events and the resultant suppression of the alpha interferon (IFN-α) response were confirmed by a luciferase reporter gene assay with five tandem repeats of the IFN-α-stimulated response element as an enhancer element of the firely luciferase gene. STAT-1 production was restored and detectable in FLMT cells treated with a proteosome inhibitor, such as MG132 or lactacystin. In the presence of MG132, ubiquitination of STAT-1 and the interaction of MuV-V with STAT-1 were demonstrated in FLMT cells by immunoprecipitation with anti-STAT-1 antibody. The same results for the interaction and ubiquitination were obtained in experiments with an expression vector for a C-terminal deletion mutant of STAT-1. The truncated STAT-1 molecules were degraded in the presence of MuV-V. Therefore, the C-terminal region (transcriptional activation and Src homology 2 domains) of STAT-1 is not necessary for its degradation caused by MuV-V. Our data suggest that MuV-V promotes ubiquitination and degradation of STAT-1.

scholarly journals A single amino acid in E-cadherin responsible for host specificity towards the human pathogen Listeria monocytogenes

1999 ◽  
Vol 18 (14) ◽  
pp. 3956-3963 ◽  
Author(s):  
Marc Lecuit ◽  
Shaynoor Dramsi ◽  
Cara Gottardi ◽  
Mary Fedor-Chaiken ◽  
Barry Gumbiner ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Amino Acid ◽  
Host Specificity ◽  
Single Amino Acid ◽  
Human Pathogen ◽  
E Cadherin

scholarly journals Engineered Resistance Against Papaya ringspot virus in Venezuelan Transgenic Papayas

Plant Disease ◽  
2004 ◽  
Vol 88 (5) ◽  
pp. 516-522 ◽  
Author(s):  
Gustavo Fermin ◽  
Valentina Inglessis ◽  
Cesar Garboza ◽  
Sairo Rangel ◽  
Manuel Dagert ◽  
...  
Keyword(s):  
Amino Acid ◽  
Agrobacterium Tumefaciens ◽  
Coat Protein ◽  
Amino Acid Sequence ◽  
Sequence Similarity ◽  
Ringspot Virus ◽  
Amino Acid Sequence Similarity ◽  
Papaya Ringspot Virus ◽  
Local Varieties ◽  
Cp Gene

Local varieties of papaya grown in the Andean foothills of Mérida, Venezuela, were transformed independently with the coat protein (CP) gene from two different geographical Papaya ringspot virus (PRSV) isolates, designated VE and LA, via Agrobacterium tumefaciens. The CP genes of both PRSV isolates show 92 and 96% nucleotide and amino acid sequence similarity, respectively. Four PRSV-resistant R0 plants were intercrossed or selfed, and the progenies were tested for resistance against the homologous isolates VE and LA, and the heterologous isolates HA (Hawaii) and TH (Thailand) in greenhouse conditions. Resistance was affected by sequence similarity between the transgenes and the challenge viruses: resistance values were higher for plants challenged with the homologous isolates (92 to 100% similarity) than with the Hawaiian (94% similarity) and, lastly, Thailand isolates (88 to 89% similarity). Our results show that PRSV CP gene effectively protects local varieties of papaya against homologous and heterologous isolates of PRSV.

SERPINS: ANTITHROMBIN AND OTHER INHIBITORS OF COAGULATION AND FIBRINOLYSIS. EVIDENCE FROM AMINO ACID SEQUENCES

1987 ◽  
Author(s):  
R W Carrell ◽  
P D Christey ◽  
D R Boswell
Keyword(s):  
Amino Acid ◽  
Inhibitory Activity ◽  
Inflammatory Responses ◽  
Three Dimensional ◽  
Activated Protein C ◽  
Amino Acid Sequences ◽  
Single Amino Acid ◽  
General Function ◽  
Topological Features ◽  
Coagulation And Fibrinolysis

A number of the key inhibitors of coagulation and fibrinolysis have recently been shown to be members of the same superfamily of serine protease inhibitors, the serpins. The archetypes of the group are alpha-l-antitrypsin and antithrombin and it includes antiplasmin, C1-inhibitor, heparin cofactor II and the newly recognised inhibitors of plasminogen activators and activated Protein C. Alignment of their structures shows that they have the same skeletal three-dimensional conformation and, by inference, the same general function mechanisms.The serpins have a reactive centre, primarily dependent on a single amino acid, exteriorly placed on a stressed peptide loop. This functions by offering the cognate protease a high-affinity substrate that resists complete cleavage to form a tight 1:1 complex of inhibitor and protease that is subsequently removed from the circulation. The loop is vulnerable to cleavage with resulting loss of inhibitory activity. This irreversible switch is utilised: pathologically by venom and invasive bacterial proteases; and physiologically by the neutrophil leucocyte to modify local inflammatory responses. These mechanisms contribute to the changes seen in DIC and the shock syndromes.Modelling of antithrombin indicates the likely topological features involved in the binding of heparin, namely a sphere of positive charge centred on the A and D helices and involving Arg 47, Lys 125, Arg 129 and probably Arg 132 and Lys 133.Because the serpins are largely dependent for their specificityon a single amino acid it is now possible to precisely tailor inhibitory activity by site specific mutation. This has been used to produce recombinant antitrypsins that function as an improved inhibitor of neutrophil proteases (valine or leucine reactive centre), or as an analogue of antithrombin (arginine reactive centre). An elegant application of this approach is the engineered mutants of antiplasmin recently described by Holmes, Collen and colleagues (Leuven).

Calcium binding to abnormal fibrinogens with a single amino acid replacement in the NH2-terminal region of fibrin α - or β-chain

1992 ◽  
Vol 67 (5) ◽  
pp. 613-618 ◽  
Author(s):  
Nobuhiko Yoshida ◽  
Hajime Hirata ◽  
Shinji Asakura ◽  
Kensuke Yamazumi ◽  
Michio Matsuda ◽  
...  
Keyword(s):  
Amino Acid ◽  
Calcium Binding ◽  
Amino Acid Replacement ◽  
Terminal Region ◽  
Single Amino Acid ◽  
Β Chain

scholarly journals Potent Antibody-Mediated Neutralization and Evolution of Antigenic Escape Variants of Simian Immunodeficiency Virus Strain SIVmac239 In Vivo

2008 ◽  
Vol 82 (19) ◽  
pp. 9739-9752 ◽  
Author(s):  
Shuji Sato ◽  
Eloisa Yuste ◽  
William A. Lauer ◽  
Eun Hyuk Chang ◽  
Jennifer S. Morgan ◽  
...  
Keyword(s):  
Amino Acid ◽  
Time Course ◽  
Neutralizing Antibody ◽  
Synonymous Substitution ◽  
Viral Envelope ◽  
Single Amino Acid ◽  
Nucleotide Substitutions ◽  
Recombinant Viruses ◽  
Synonymous Substitution Rates

ABSTRACT Here, we describe the evolution of antigenic escape variants in a rhesus macaque that developed unusually high neutralizing antibody titers to SIVmac239. By 42 weeks postinfection, 50% neutralization of SIVmac239 was achieved with plasma dilutions of 1:1,000. Testing of purified immunoglobulin confirmed that the neutralizing activity was antibody mediated. Despite the potency of the neutralizing antibody response, the animal displayed a typical viral load profile and progressed to terminal AIDS with a normal time course. Viral envelope sequences from week 16 and week 42 plasma contained an excess of nonsynonymous substitutions, predominantly in V1 and V4, including individual sites with ratios of nonsynonymous to synonymous substitution rates (dN/dS) highly suggestive of strong positive selection. Recombinant viruses encoding envelope sequences isolated from these time points remained resistant to neutralization by all longitudinal plasma samples, revealing the failure of the animal to mount secondary responses to the escaped variants. Substitutions at two sites with significant dN/dS values, one in V1 and one in V4, were independently sufficient to confer nearly complete resistance to neutralization. Substitutions at three additional sites, one in V4 and two in gp41, conferred moderate to high levels of resistance when tested individually. All the amino acid changes leading to escape resulted from single nucleotide substitutions. The observation that antigenic escape resulted from individual, single amino acid replacements at sites well separated in current structural models of Env indicates that the virus can utilize multiple independent pathways to rapidly achieve similar levels of resistance.

scholarly journals Antigenic variants with amino acid deletions clarify a neutralizing epitope specific for influenza B virus Victoria group strains

2001 ◽  
Vol 82 (9) ◽  
pp. 2169-2172 ◽  
Author(s):  
Naoko Nakagawa ◽  
Ritsuko Kubota ◽  
Toshimasa Nakagawa ◽  
Yoshinobu Okuno
Keyword(s):  
Amino Acid ◽  
Amino Acid Substitution ◽  
Haemagglutination Inhibition ◽  
Three Dimensional ◽  
Amino Acid Sequences ◽  
Single Amino Acid Substitution ◽  
Single Amino Acid ◽  
Influenza B Virus ◽  
Influenza B ◽  
B Virus

To study the neutralizing epitopes of influenza B virus Victoria group strains, two monoclonal antibodies (MAbs) were used to select antigenic variants of the virus. MAbs 10B8 and 8E6 were found to react with B/Victoria group strains in three tests, peroxidase–antiperoxidase staining, haemagglutination inhibition and neutralization tests; no reactivity with B/Yamagata group strains was observed. Analysis of the deduced amino acid sequences of 10B8-induced variants identified a single amino acid deletion at residue 165 or 170, as well as a single amino acid substitution at residues 164 (Asp→Tyr), 165 (Asn→Ser or Thr) or 203 (Lys→Thr or Asn). A single amino acid substitution at residue 241 (Pro→Ser) was observed in 8E6-induced variants. Three-dimensional analysis showed that the epitopes for both MAbs were situated in close proximity to each other. Since B/Yamagata group strains are characterized by amino acid deletions at residues 164–166, the epitope for MAb 10B8 is strictly specific for B/Victoria group strains.

scholarly journals Comparação da seqüência de nucleotídeos do gene da proteína capsidial de estirpes severas e premunizantes do Papaya ringspot virus

2003 ◽  
Vol 28 (6) ◽  
pp. 678-681 ◽  
Author(s):  
Marilia G. S. Della Vecchia ◽  
Luis E. A. Camargo ◽  
Jorge A. M. Rezende
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Core Region ◽  
Amino Acid Sequences ◽  
Ringspot Virus ◽  
Papaya Ringspot Virus ◽  
Specific Primers ◽  
Sequence Comparisons ◽  
The Core ◽  
Cp Gene

This study compared three mild and three severe strains of Papaya ringspot virus - type W (PRSV-W), based on nucleotide and amino acid sequences of the capsid protein (CP) gene. The CP nucleotide sequences of the mild strains shared 98% to 100% identity. When compared to the severe strains the identity ranged from 93% to 95%, except in the case of PRSV-W-2R, which resulted from reversion of the mild strains PRSV-W-2. The CP sequence of the reverting strain showed 100% identity with the sequence of its parental strain. An insertion of six nucleotides in the core region of the CP gene, which reflected the addition of two amino acids (Asn and Asp) in the deduced sequence of the protein, was found in all mild strains. These sequence comparisons were used to design strain-specific primers that were used to specifically amplify regions for either the mild or severe strains.

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