title: The strength of the template effect attracting nucleotides to naked DNA.
abstract: The transmission of genetic information relies on Watson-Crick base pairing between nucleoside phosphates and template bases in template-primer complexes. Enzyme-free primer extension is the purest form of the transmission process, without any chaperon-like effect of polymerases. This simple form of copying of sequences is intimately linked to the origin of life and provides new opportunities for reading genetic information. Here, we report the dissociation constants for complexes between (deoxy)nucleotides and template-primer complexes, as determined by nuclear magnetic resonance and the inhibitory effect of unactivated nucleotides on enzyme-free primer extension. Depending on the sequence context, Kd's range from 280 mM for thymidine monophosphate binding to a terminal adenine of a hairpin to 2 mM for a deoxyguanosine monophosphate binding in the interior of a sequence with a neighboring strand. Combined with rate constants for the chemical step of extension and hydrolytic inactivation, our quantitative theory explains why some enzyme-free copying reactions are incomplete while others are not. For example, for GMP binding to ribonucleic acid, inhibition is a significant factor in low-yielding reactions, whereas for amino-terminal DNA hydrolysis of monomers is critical. Our results thus provide a quantitative basis for enzyme-free copying.
authors.affiliation: Institute for Organic Chemistry, University of Stuttgart, 70569 Stuttgart, Germany.
authors.forename: Eric
authors.initials: E
authors.lastname: Kervio
authors.affiliation: Institute for Organic Chemistry, University of Stuttgart, 70569 Stuttgart, Germany.
authors.forename: Birgit
authors.initials: B
authors.lastname: Claasen
authors.affiliation: Fachbereich Chemie, Universität Konstanz, 78457 Konstanz, Germany.
authors.forename: Ulrich E
authors.initials: UE
authors.lastname: Steiner
authors.affiliation: Institute for Organic Chemistry, University of Stuttgart, 70569 Stuttgart, Germany lehrstuhl-2@oc.uni-stuttgart.de.
authors.forename: Clemens
authors.initials: C
authors.lastname: Richert
mesh_terms: D004247:DNA / Q000737:chemistry* / Q000378:metabolism*; D017931:DNA Primers / Q000378:metabolism; D003854:Deoxyribonucleotides / Q000737:chemistry / Q000378:metabolism*; D013698:Templates, Genetic
chemical_list: D017931:DNA Primers; D003854:Deoxyribonucleotides; D004247:DNA