Screening and identification of aptamers against the recombinant transpeptidase domain of PBP 2a / 重庆医学

ABSTRACT

Objective To screen and identify the aptamers of the recombinant transpeptidase domain of PBP2a(penicillin binding protein 2a ,PBP2a) .Methods By using the recombinant transpeptidase domain of PBP2a as the screening target ,oligonucle-otides which were capable of specifically binding to the protein were screened by a random oligonucleotide library through the stem -atic evolution of ligand by exponential enrichment (SELEX )technique .The ssDNA was cloned and sequenced ,and the secondary structure of aptamer clones was predicted with mfold program .Results After 11 cycles of the selection ,the aptamers which were capable of binding to PBP2a with high affinity have been selected .40 clones from the 8 and 10 cycles were selected randomly and se-quenced .The aptamers obtained had no obvious homology according to their sequences by the sequence alignments ,and the 40 aptamers were classified to three groups according to their secondary structures .The aptamer 13 was found to be specific for the target protein with the highest affinity .Conclusion Aptamers for the recombinant transpeptidase domain of PBP2a with high affili-ty and specificity were successfully screened by SELEX ,which lays a foundation for exploring new ways of diagnosis and treatment of MRSA infection .