摘要
The cDNA coding for the group 9 allergen of Dermatophagoides farinae (Hughes) (Acari: Pyroglyphidae) from southeast China was cloned and sequenced in the present study. There were five mismatched nucleotides in five obtained cDNA clones resulting in two incompatible amino acid residues in allergen active part, suggesting that Der f 9 allergen might have sequence polymorphism. Bioinformatics analysis revealed that the matured Der f 9 allergen has a molecular weight of 24216.3 Da and theoretical pI of 8.75, and maybe a member of serine proteases. Similarities in amino acid sequences between Der f 9 and the group 9 allergens of other dust mite species, viz. Ale o 9, Blo t 9, sui m 9 were 57%, 61%, 62%, respectively. However, the similarity between Der f 9 and trypsin-like serine protease of D. pteronyssinus, serine protease LM-1 of D. pteronyssinus were 70%, 87%, respectively. The similarity between Der f 9 and Der f 6 was 40%. Phylogenetic analysis indicated that Der f 9 and Ale o 9, Blo t 9, sui m 9, trypsin-like serine protease of D. pteronyssinus, serine protease LM-1 of D. pteronyssinus were clustered together with 95% bootstrap support. Bioinformatics-driven characterization of Der f 9 allergen as conducted here may contribute to diagnostic and therapeutic applications for dust mite allergies.
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