Diversification of DNA-Binding Specificity by Permissive and Specificity-Switching Mutations in the ParB/Noc Protein Family.Jalal, A.S.B., Tran, N.T., Stevenson, C.E., Chan, E.W., Lo, R., Tan, X., Noy, A., Lawson, D.M., Le, T.B.K.
(2020) Cell Rep 32: 107928-107928
- PubMed: 32698006
- DOI: 10.1016/j.celrep.2020.107928
- Primary Citation of Related Structures:
- PubMed Abstract:
Specific interactions between proteins and DNA are essential to many biological processes. Yet, it remains unclear how the diversification in DNA-binding specificity was brought about, and the mutational paths that led to changes in specificity are u ...
Specific interactions between proteins and DNA are essential to many biological processes. Yet, it remains unclear how the diversification in DNA-binding specificity was brought about, and the mutational paths that led to changes in specificity are unknown. Using a pair of evolutionarily related DNA-binding proteins, each with a different DNA preference (ParB [Partitioning Protein B] and Noc [Nucleoid Occlusion Factor], which both play roles in bacterial chromosome maintenance), we show that specificity is encoded by a set of four residues at the protein-DNA interface. Combining X-ray crystallography and deep mutational scanning of the interface, we suggest that permissive mutations must be introduced before specificity-switching mutations to reprogram specificity and that mutational paths to new specificity do not necessarily involve dual-specificity intermediates. Overall, our results provide insight into the possible evolutionary history of ParB and Noc and, in a broader context, might be useful for understanding the evolution of other classes of DNA-binding proteins.
Department of Molecular Microbiology, John Innes Centre, Norwich NR4 7UH, UK. Electronic address: firstname.lastname@example.org.