scholarly journals Mutational Analysis of the Amino Acid Residues Essential for thecisandtransCleavage Activity of the Potato Virus Y 50-kDa Protease

1993 ◽  
Vol 57 (9) ◽  
pp. 1536-1540 ◽  
Author(s):  
Yukiko Yoshida ◽  
Makoto Hidaka ◽  
Haruhiko Masaki ◽  
Takeshi Uozumi
Keyword(s):  
Amino Acid ◽  
Potato Virus ◽  
Potato Virus Y ◽  
Mutational Analysis ◽  
Amino Acid Residues

scholarly journals Mutations in Potato virus Y Genome-Linked Protein Determine Virulence Toward Recessive Resistances in Capsicum annuum and Lycopersicon hirsutum

2004 ◽  
Vol 17 (3) ◽  
pp. 322-329 ◽  
Author(s):  
Benoît Moury ◽  
Caroline Morel ◽  
Elisabeth Johansen ◽  
Laurent Guilbaud ◽  
Sylvie Souche ◽  
...  
Keyword(s):  
Amino Acid ◽  
Capsicum Annuum ◽  
Potato Virus ◽  
Potato Virus Y ◽  
Cdna Clones ◽  
Lycopersicon Hirsutum ◽  
Potato Virus A ◽  
Single Nucleotide Change ◽  
Protein Encoding

The recessive resistance genes pot-1 and pvr2 in Lycopersicon hirsutum and Capsicum annuum, respectively, control Potato virus Y (PVY) accumulation in the inoculated leaves. Infectious cDNA molecules from two PVY isolates differing in their virulence toward these resistances were obtained using two different strategies. Chimeras constructed with these cDNA clones showed that a single nucleotide change corresponding to an amino acid substitution (Arg119His) in the central part of the viral protein genome-linked (VPg) was involved in virulence toward the pot-1 resistance. On the other hand, 15 nucleotide changes corresponding to five putative amino acid differences in the same region of the VPg affected virulence toward the pvr21 and pvr22 resistances. Substitution models identified six and five codons within the central and C terminal parts of the VPg for PVY and for the related potyvirus Potato virus A, respectively, which undergo positive selection. This suggests that the role of the VPg-encoding region is determined by the protein and not by the viral RNA apart from its protein-encoding capacity.

scholarly journals Identification by Mutational Analysis of Amino Acid Residues Essential in the Chaperone Function of Calreticulin

2005 ◽  
Vol 281 (4) ◽  
pp. 2338-2346 ◽  
Author(s):  
Virginie Martin ◽  
Jody Groenendyk ◽  
Simone S. Steiner ◽  
Lei Guo ◽  
Monika Dabrowska ◽  
...  
Keyword(s):  
Amino Acid ◽  
Mutational Analysis ◽  
Amino Acid Residues ◽  
Chaperone Function

Mutational analysis of positively charged amino acid residues of Uukuniemi phlebovirus nucleocapsid protein

2012 ◽  
Vol 167 (1) ◽  
pp. 118-123 ◽  
Author(s):  
Anna Katz ◽  
Alexander N. Freiberg ◽  
Vera Backström ◽  
Liisa Holm ◽  
Antti Vaheri ◽  
...  
Keyword(s):  
Amino Acid ◽  
Nucleocapsid Protein ◽  
Mutational Analysis ◽  
Amino Acid Residues ◽  
Positively Charged

scholarly journals Different Mutations in the Genome-Linked Protein VPg of Potato virus Y Confer Virulence on the pvr23 Resistance in Pepper

2006 ◽  
Vol 19 (5) ◽  
pp. 557-563 ◽  
Author(s):  
Valérie Ayme ◽  
Sylvie Souche ◽  
Carole Caranta ◽  
Mireille Jacquemond ◽  
Joël Chadœuf ◽  
...  
Keyword(s):  
Amino Acid ◽  
Genetic Drift ◽  
Potato Virus ◽  
High Frequency ◽  
Potato Virus Y ◽  
Relative Fitness ◽  
Amino Acid Substitutions ◽  
Nucleotide Substitutions ◽  
Single Nucleotide ◽  
Pepper Plants

Five different amino acid substitutions in the VPg of Potato virus Y were shown to be independently responsible for virulence toward pvr23 resistance gene of pepper. A consequence of these multiple mutations toward virulence involving single nucleotide substitutions is a particularly high frequency of resistance breaking (37% of inoculated plants from the first inoculation) and suggests a potentially low durability of pvr23 resistance. These five mutants were observed with significantly different frequencies, one of them being overrepresented. Genetic drift alone could not explain the observed distribution of virulent mutants. More plausible scenarios were obtained by taking into account either the relative substitution rates, the relative fitness of the mutants in pvr23 pepper plants, or both.

scholarly journals Surface-exposed Amino Acid Residues of HPV16 L1 Protein Mediating Interaction with Cell Surface Heparan Sulfate

2007 ◽  
Vol 282 (38) ◽  
pp. 27913-27922 ◽  
Author(s):  
Maren Knappe ◽  
Sabrina Bodevin ◽  
Hans-Christoph Selinka ◽  
Dorothe Spillmann ◽  
Rolf E. Streeck ◽  
...  
Keyword(s):  
Amino Acid ◽  
Cell Surface ◽  
Heparan Sulfate ◽  
Capsid Protein ◽  
Mutational Analysis ◽  
Cell Attachment ◽  
Human Papillomaviruses ◽  
Amino Acid Residues ◽  
Cell Binding ◽  
Lysine Residues

Efficient infection of cells by human papillomaviruses (HPVs) and pseudovirions requires primary interaction with cell surface proteoglycans with apparent preference for species carrying heparan sulfate (HS) side chains. To identify residues contributing to virus/cell interaction, we performed point mutational analysis of the HPV16 major capsid protein, L1, targeting surface-exposed amino acid residues. Replacement of lysine residues 278, 356, or 361 for alanine reduced cell binding and infectivity of pseudovirions. Various combinations of these amino acid exchanges further decreased cell attachment and infectivity with residual infectivity of less than 5% for the triple mutant, suggesting that these lysine residues cooperate in HS binding. Single, double, or triple exchanges for arginine did not impair infectivity, demonstrating that interaction is dependent on charge distribution rather than sequence-specific. The lysine residues are located within a pocket on the capsomere surface, which was previously proposed as the putative receptor binding site. Fab fragments of binding-neutralizing antibody H16.56E that recognize an epitope directly adjacent to lysine residues strongly reduced HS-mediated cell binding, further corroborating our findings. In contrast, mutation of basic surface residues located in the cleft between capsomeres outside this pocket did not significantly reduce interaction with HS or resulted in assembly-deficient proteins. Computer-simulated heparin docking suggested that all three lysine residues can form hydrogen bonds with 2-O-, 6-O-, and N-sulfate groups of a single HS molecule with a minimal saccharide domain length of eight monomer units. This prediction was experimentally confirmed in binding experiments using capsid protein, heparin molecules of defined length, and sulfate group modifications.

scholarly journals Mutational Analysis of Xanthomonas Harpin HpaG Identifies a Key Functional Region That Elicits the Hypersensitive Response in Nonhost Plants

2004 ◽  
Vol 186 (18) ◽  
pp. 6239-6247 ◽  
Author(s):  
Jung-Gun Kim ◽  
Eunkyung Jeon ◽  
Jonghee Oh ◽  
Jae Sun Moon ◽  
Ingyu Hwang
Keyword(s):  
Amino Acid ◽  
Hypersensitive Response ◽  
Mutational Analysis ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Amino Acid Residues ◽  
Tobacco Plants ◽  
Functional Region ◽  
Amino Acid Peptide ◽  
Α Helix

ABSTRACT HpaG is a type III-secreted elicitor protein of Xanthomonas axonopodis pv. glycines. We have determined the critical amino acid residues important for hypersensitive response (HR) elicitation by random and site-directed mutagenesis of HpaG and its homolog XopA. A plasmid clone carrying hpaG was mutagenized by site-directed mutagenesis, hydroxylamine mutagenesis, and error-prone PCR. A total of 52 mutants were obtained, including 51 single missense mutants and 1 double missense mutant. The HR elicitation activity was abolished in the two missense mutants [HpaG(L50P) and HpaG(L43P/L50P)]. Seven single missense mutants showed reduced activity, and the HR elicitation activity of the rest of the mutants was similar to that of wild-type HpaG. Mutational and deletion analyses narrowed the region essential for elicitor activity to the 23-amino-acid peptide (H2N-NQGISEKQLDQLLTQLIMALLQQ-COOH). A synthetic peptide of this sequence possessed HR elicitor activity at the same concentration as the HpaG protein. This region has 78 and 74% homology with 23- and 27-amino-acid regions of the HrpW harpin domains, respectively, from Pseudomonas and Erwinia spp. The secondary structure of the peptide is predicted to be an α-helix, as is the HrpW region that is homologous to HpaG. The predicted α-helix of HpaG is probably critical for the elicitation of the HR in tobacco plants. In addition, mutagenesis of a xopA gene yielded two gain-of-function mutants: XopA(F48L) and XopA(F48L/M52L). These results indicate that the 12 amino acid residues between L39 and L50 of HpaG have critical roles in HR elicitation in tobacco plants.

Mutational analysis of amino acid residues involved in IgE-binding to the Malassezia sympodialis allergen Mala s 11

2008 ◽  
Vol 46 (2) ◽  
pp. 294-303 ◽  
Author(s):  
Monica Vilhelmsson ◽  
Andreas G. Glaser ◽  
Daniel Badia Martinez ◽  
Margit Schmidt ◽  
Catharina Johansson ◽  
...  
Keyword(s):  
Amino Acid ◽  
Mutational Analysis ◽  
Amino Acid Residues ◽  
Ige Binding
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