title: Interactions of in vitro selected fluorogenic peptide aptamers with calmodulin.
abstract: OBJECTIVE
  We examined the importance of aptamer usage under the same condition as the selection process by employing the previously selected aptamers for calmodulin (CaM) which includes a non-natural fluorogenic amino acid, 7-nitro-2,1,3-benzoxadiazole.
  
  
  RESULTS
  We added five amino acids at the N-terminus which was employed for the selection and then we tested the affinity and selectivity for CaM binding. Surface plasmon resonance and fluorescence measurements showed that the additional amino acids for one of the aptamers drastically improved binding affinity to CaM, indicating the importance of aptamer use under the same conditions as the selection process. Such drastic improvement in affinity was not observed for the sequence which had been reported previously. Nuclear magnetic resonance data identified that the primary binding site is located in a C-terminal of CaM and the additional residues enhance interactions with CaM.
  
  
  CONCLUSIONS
  We found that the addition of the common sequence, which was employed for ribosome display, makes the affinity of a selected peptide as strong as the previously reported peptide.
authors.affiliation: Nano Medical Engineering Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.|Graduate School of Biological Science, Tokyo Metropolitan University, 1-1 Minami-Osawa, Tokyo, 192-0397, Japan.
authors.forename: Yasodha
authors.initials: Y
authors.lastname: Manandhar
authors.affiliation: Nano Medical Engineering Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: Department of Chemistry, Tokyo Metropolitan University, 1-1 Minami-Osawa, Tokyo, 192-0397, Japan.
authors.forename: Jin
authors.initials: J
authors.lastname: Inoue
authors.affiliation: Department of Life Science and Technology, School of Life Science and Technology, Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro-ku, Tokyo, 152-8550, Japan.
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Hayashi
authors.affiliation: Nano Medical Engineering Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.|Emergent Bioengineering Materials Research Team, RIKEN Center for Emergent Matter Science, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
authors.forename: Takanori
authors.initials: T
authors.lastname: Uzawa
authors.affiliation: Department of Chemistry, Tokyo Metropolitan University, 1-1 Minami-Osawa, Tokyo, 192-0397, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Ito
authors.affiliation: Nano Medical Engineering Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.|Graduate School of Biological Science, Tokyo Metropolitan University, 1-1 Minami-Osawa, Tokyo, 192-0397, Japan.
authors.forename: Toshiro
authors.initials: T
authors.lastname: Aigaki
authors.affiliation: Nano Medical Engineering Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan. y-ito@riken.jp.|Graduate School of Biological Science, Tokyo Metropolitan University, 1-1 Minami-Osawa, Tokyo, 192-0397, Japan. y-ito@riken.jp.|Emergent Bioengineering Materials Research Team, RIKEN Center for Emergent Matter Science, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan. y-ito@riken.jp.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Ito
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D052158:Aptamers, Peptide / Q000737:chemistry / Q000378:metabolism*; D002147:Calmodulin / Q000378:metabolism*; D002417:Cattle; D005453:Fluorescence; D009682:Magnetic Resonance Spectroscopy; D011485:Protein Binding; D012995:Solubility; D020349:Surface Plasmon Resonance
chemical_list: D052158:Aptamers, Peptide; D002147:Calmodulin
keywords: 7-nitro-2,1,3-benzoxadiazole; Calmodulin; Fluorescence; NMR; Signaling peptide aptamer; Surface plasmon resonance