Amino Acid Substitution in Par j 2 Recombinant Allergen and Its Effect on IgE Binding Capacity

Abstract Background Artemisia weed pollen allergy is important in the northern hemisphere. While over 350 species of this genus have been recorded, there has been no full investigation into whether different species may affect the allergen diagnosis and treatment. This study aimed to evaluate the variations in amino acid sequences and the content of major allergens, and how these affect specific IgE binding capacity in representative Artemisia species. Methods Six representative Artemisia species from China and Artemisia vulgaris from Europe were used to determine allergen amino acid sequences by transcriptome, gene sequencing and mass spectrometry of the purified allergen component proteins. Sandwich ELISAs were developed and applied for Art v 1, Art v 2 and Art v 3 allergen quantification in different species. Aqueous pollen extracts and purified allergen components were used to assess IgE binding by ELISA and ImmunoCAP with mugwort allergic patient serum pools and individual sera from five areas in China. Results The Art v 1 and Art v 2 homologous allergen sequences in the seven Artemisia species were highly conserved. Art v 3 type allergens in A. annua and A. sieversiana were more divergent compared to A. argyi and A. vulgaris. The allergen content of Art v 1 group in the seven extracts ranged from 3.4% to 7.1%, that of Art v 2 from 1.0% to 3.6%, and Art v 3 from 0.3% to 10.5%. The highest IgE binding potency for most Chinese Artemisia allergy patients was with A. annua pollen extract, followed by A. vulgaris and A. argyi, with A. sieversiana significantly lower. Natural Art v 1-3 isoallergens from different species have almost equivalent IgE binding capacity in Artemisia allergic patients from China. Conclusion and clinical relevance There was high sequence similarity but different content of the three group allergens from different Artemisia species. Choice of Artemisia annua and A. argyi pollen source for diagnosis and immunotherapy is recommended in China.

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Effect of Point Mutations on Structural and Allergenic Properties of the Lentil Allergen Len c 3

Membranes ◽

10.3390/membranes11120939 ◽

2021 ◽

Vol 11 (12) ◽

pp. 939

Author(s):

Daria N. Melnikova ◽

Ekaterina I. Finkina ◽

Ivan V. Bogdanov ◽

Anastasia A. Ignatova ◽

Natalia S. Matveevskaya ◽

...

Keyword(s):

Amino Acid ◽

Binding Capacity ◽

Point Mutations ◽

Site Directed Mutagenesis ◽

Amino Acid Residues ◽

Lipid Transfer ◽

Ige Binding ◽

Allergenic Potential ◽

Binding Epitope ◽

Clinically Significant

Plant lipid transfer proteins (LTPs) are known to be clinically significant allergens capable of binding various lipid ligands. Recent data showed that lipid ligands affected the allergenic properties of plant LTPs. In this work, we checked the assumption that specific amino acid residues in the Len c 3 structure can play a key role both in the interaction with lipid ligands and IgE-binding capacity of the allergen. The recombinant analogues of Len c 3 with the single or double substitutions of Thr41, Arg45 and/or Tyr80 were obtained by site-directed mutagenesis. All these amino acid residues are located near the “bottom” entrance to the hydrophobic cavity of Len c 3 and are likely included in the IgE-binding epitope of the allergen. Using a bioinformatic approach, circular dichroism and fluorescence spectroscopies, ELISA, and experiments mimicking the allergen Len c 3 gastroduodenal digestion we showed that the substitution of all the three amino acid residues significantly affected structural organization of this region and led both to a change of the ligand-binding capacity and the allergenic potential of Len c 3.

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Hubsm: A Novel Amino Acid Substitution Matrix for Comparing Hub Proteins

International Journal of Advanced Research in Computer Science and Software Engineering ◽

10.23956/ijarcsse.v7i8.53 ◽

2017 ◽

Vol 7 (8) ◽

pp. 212

Author(s):

Renganayaki G. ◽

Achuthsankar S. Nair

Keyword(s):

Amino Acid ◽

Amino Acid Substitution ◽

Low Complexity ◽

Database Search ◽

Substitution Matrix ◽

Compositional Bias ◽

Sequence Alignments ◽

Amino Acid Substitution Matrix ◽

Alignment Algorithms ◽

Hub Proteins

Sequence alignment algorithms and database search methods use BLOSUM and PAM substitution matrices constructed from general proteins. These de facto matrices are not optimal to align sequences accurately, for the proteins with markedly different compositional bias in the amino acid. In this work, a new amino acid substitution matrix is calculated for the disorder and low complexity rich region of Hub proteins, based on residue characteristics. Insights into the amino acid background frequencies and the substitution scores obtained from the Hubsm unveils the residue substitution patterns which differs from commonly used scoring matrices .When comparing the Hub protein sequences for detecting homologs, the use of this Hubsm matrix yields better results than PAM and BLOSUM matrices. Usage of Hubsm matrix can be optimal in database search and for the construction of more accurate sequence alignments of Hub proteins.

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