title: Thiazotropsin aggregation and its relationship to molecular recognition in the DNA minor groove.
abstract: Aggregated states have been alluded to for many DNA minor groove binders but details of the molecule-on-molecule relationship have either been under-reported or ignored. Here we report our findings from ITC and NMR measurements carried out with AIK-18/51, a compound representative of the thiazotropsin class of DNA minor groove binders. The free aqueous form of AIK-18/51 is compared with that found in its complex with cognate DNA duplex d(CGACTAGTCG)2. Molecular self-association of AIK-18/51 is consistent with anti-parallel, face-to-face dimer formation, the building block on which the molecule aggregates. This underlying structure is closely allied to the form found in the ligand's DNA complex. NMR chemical shift and diffusion measurements yield a self-association constant Kass=(61±19)×10(3)M(-1) for AIK-18/51 that fits with a stepwise self-assembly model and is consistent with ITC data. The deconstructed energetics of this assembly process are reported with respect to a design strategy for ligand/DNA recognition.
authors.affiliation: WestCHEM Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow G1 1XL, United Kingdom.
authors.forename: Marie-Virginie
authors.initials: MV
authors.lastname: Salvia
authors.forename: Fiona
authors.initials: F
authors.lastname: Addison
authors.forename: Hasan Y
authors.initials: HY
authors.lastname: Alniss
authors.forename: Niklaas J
authors.initials: NJ
authors.lastname: Buurma
authors.forename: Abedawn I
authors.initials: AI
authors.lastname: Khalaf
authors.forename: Simon P
authors.initials: SP
authors.lastname: Mackay
authors.forename: Nahoum G
authors.initials: NG
authors.lastname: Anthony
authors.forename: Colin J
authors.initials: CJ
authors.lastname: Suckling
authors.forename: Maxim P
authors.initials: MP
authors.lastname: Evstigneev
authors.forename: Adrián Hernandez
authors.initials: AH
authors.lastname: Santiago
authors.forename: Roger D
authors.initials: RD
authors.lastname: Waigh
authors.forename: John A
authors.initials: JA
authors.lastname: Parkinson
mesh_terms: D001665:Binding Sites; D004247:DNA / Q000737:chemistry*; D004058:Diffusion; D008958:Models, Molecular; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D013844:Thiazoles / Q000737:chemistry*
chemical_list: D013844:Thiazoles; C488075:thiazotropsin A; C512183:thiazotropsin B; D004247:DNA
keywords: DNA minor groove; ITC; Ligand-aggregation; Molecular recognition; NMR; Self-diffusion