Switching DNA-binding specificity by unnatural amino acid substitution

Maiti, Atanu ; Roy, Siddhartha (2005) Switching DNA-binding specificity by unnatural amino acid substitution Nucleic Acids Research, 33 (18). pp. 5896-5903. ISSN 0305-1048

PDF - Publisher Version

Official URL: http://nar.oxfordjournals.org/content/33/18/5896.a...

Related URL: http://dx.doi.org/10.1093/nar/gki899


The specificity of protein-nucleic acid recognition is believed to originate largely from hydrogen bonding between protein polar atoms, primarily side-chain and polar atoms of nucleic acid bases. One way to design new nucleic acid binding proteins of novel specificity is by structure-guided alterations of the hydrogen bonding patterns of a nucleic acid-protein complex. We have used cI repressor of bacteriophage λ as a model system. In the λ-repressor-DNA complex, the ε-NH2 group (hydrogen bond donor) of lysine-4 of λ-repressor forms hydrogen bonds with the amide carbonyl atom of asparagine-55 (acceptor) and the O6 (acceptor) of CG6 of operator site OL1. Substitution of lysine-4 (two donors) by iso-steric S-(2-hydroxyethyl)-cysteine (one donor and one acceptor), by site-directed mutagenesis and chemical modification, leads to switch of binding specificity of λ-repressor from C:G to T:A at position 6 of OL1. This suggests that unnatural amino acid substitutions could be a simple way of generating nucleic acid binding proteins of altered specificity.

Item Type:Article
Source:Copyright of this article belongs to Oxford University Press.
ID Code:43155
Deposited On:10 Jun 2011 06:25
Last Modified:18 May 2016 00:14

Repository Staff Only: item control page