The crystal structure of αCP1-KH3 (residues 279–356) solved to 2

Copyright information:Taken from "Structure and RNA binding of the third KH domain of poly(C)-binding protein 1"Nucleic Acids Research 2005;33(4):1213-1221.Published online 24 Feb 2005PMCID:PMC549569.© The Author 2005. Published by Oxford University Press. All rights reserved1 Å resolution depicted in () cartoon form and () as a molecular surface in the same orientation. The structure is shown from the beginning of β-strand 1 to the end of α-helix 3, since the regions outside these bounds were random coil or not visible in the density. The GXXG motif, common to this oligonucleotide-binding motif, is coloured blue. The ‘variable loop’ region between β-sheets 2 and 3 is coloured pink. These regions bound the hydrophobic oligonucleotide-binding cleft that accommodates C-rich RNA or ssDNA. () The electrostatic potential emanating from the αCP1-KH3 structure calculated using the APBS software package () (–). Potential contours are shown at +1 kT/e (blue) and −1 kT/e (red) and obtained by solution of the linearized Poisson–Boltzmann equation at 150 mM ionic strength with a solute dielectric of 2 and a solvent dielectric of 78.5. The blue contour represents a striking positive potential directing oligonucleotides to the binding cleft.