title: Searching the Sequence Space for Potent Aptamers Using SELEX in Silico.
abstract: To isolate functional nucleic acids that bind to defined targets with high affinity and specificity, which are known as aptamers, the systematic evolution of ligands by exponential enrichment (SELEX) methodology has emerged as the preferred approach. Here, we propose a computational approach, SELEX in silico, that allows the sequence space to be more thoroughly explored regarding binding of a certain target. Our approach consists of two steps: (i) secondary structure-based sequence screening, which aims to collect the sequences that can form a desired RNA motif as an enhanced initial library, followed by (ii) sequence enrichment regarding target binding by molecular dynamics simulation-based virtual screening. Our SELEX in silico method provided a practical computational solution to three key problems in aptamer sequence searching: design of nucleic acid libraries, knowledge of sequence enrichment, and identification of potent aptamers. Six potent theophylline-binding aptamers, which were isolated by SELEX in silico from a sequence space containing 4(13) sequences, were experimentally verified to bind theophylline with high affinity: Kd ranging from 0.16 to 0.52 μM, compared with the dissociation constant of the original aptamer-theophylline, 0.32 μM. These results demonstrate the significant potential of SELEX in silico as a new method for aptamer discovery and optimization.
authors.affiliation: Department of Chemistry and Chemical Biology, Harvard University , Cambridge, Massachusetts 02138, United States.
authors.forename: Qingtong
authors.initials: Q
authors.lastname: Zhou
authors.affiliation: Department of Chemistry and Chemical Biology, Harvard University , Cambridge, Massachusetts 02138, United States.|Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University , Wuxi, Jiangsu 214122, People's Republic of China.
authors.forename: Xiaole
authors.initials: X
authors.lastname: Xia
authors.forename: Zhaofeng
authors.initials: Z
authors.lastname: Luo
authors.forename: Haojun
authors.initials: H
authors.lastname: Liang
authors.affiliation: Department of Chemistry and Chemical Biology, Harvard University , Cambridge, Massachusetts 02138, United States.
authors.forename: Eugene
authors.initials: E
authors.lastname: Shakhnovich
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry* / Q000378:metabolism; D007700:Kinetics; D009690:Nucleic Acid Conformation; D059372:Nucleotide Motifs; D052156:SELEX Aptamer Technique; D013806:Theophylline / Q000737:chemistry / Q000378:metabolism
chemical_list: D052157:Aptamers, Nucleotide; D013806:Theophylline