Article ID Journal Published Year Pages File Type
9138897 Journal of Structural Biology 2005 16 Pages PDF
Abstract
Telomeres constitute the nucleoprotein ends of eukaryotic chromosomes which are essential for their proper function. Telomere end binding protein (TEBP) from Oxytricha nova was among the first telomeric proteins, which were well characterized biologically. TEBP consists of two protein subunits (α, β) and forms a ternary complex with single stranded telomeric DNA containing tandem repeats TTTTGGGG. This work presents the characterization of the thermodynamic and electrostatic properties of this complex by computational chemistry methods (continuum Poisson-Boltzmann and solvent accessible surface calculations). Our calculations give a new insight into molecular properties of studied system. Based on the thermodynamic analysis we provide a rationale for the experimental observation that α and ssDNA forms a binary complex and the β subunit joins α:ssDNA complex only after the latter is formed. Calculations of distribution of the molecular electrostatic potential for protein subunits alone and for all possible binary complexes revealed the important role of the “guiding funnel” potential generated by α:ssDNA complex. This potential may help the β subunit to dock to the already formed α:DNA intermediate in highly steric and electrostatic favorable manner. Our pKa calculations of TEBP are able to explain the experimental mobility shifts of the complex in electrophoretic non-denaturating gels.
Related Topics
Life Sciences Biochemistry, Genetics and Molecular Biology Molecular Biology
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