Extended structure of pleiotropic DNA repair‐promoting protein PprA from Deinococcus radiodurans

Abstract

Pleiotropic protein promoting DNA repair A (PprA) is a key protein facilitating the extreme radiation resistance of Deinococcus radiodurans. PprA is a unique protein to the genus Deinococcus and exists as an oligomer ranging from a tetramer to an ∼100‐mer depending on protein concentrations. Here, the X‐ray crystal structure of PprA was determined to clarify how PprA confers radiation resistance. The tertiary structure of dimeric PprA was elucidated by using mutants obtained with random and site‐directed mutagenesis methods (W183R and A139R); these mutants have disabled DNA binding and polymerization functions. Because the mutant A139R and W183R proteins have dimeric assemblies with 2 different interfaces (Interfaces 1 and 2), the linear and oligomerized PprA model was constructed as a left‐handed face‐to‐face periodic screw structure. In addition, the linear structure in solution was confirmed by small‐angle scattering experiments. The site‐directed mutational analysis identified essential basic amino acids for DNA binding. These analytical data support the hypothesis that a complex assembly of PprA molecules, which are extended and have a screw structure, surrounds and stretches the DNA strand, acting as a novel guide to colocalize the DNA strands for efficient DNA repairs.—Adachi, M., Shimizu, R., Shibazaki, C., Satoh, K., Fujiwara, S., Arai, S., Narumi, I., Kuroki, R. Extended structure of pleiotropic DNA repair‐promoting protein PprA from Deinococcus radiodurans. FASEB J. 33, 3647–3658 (2019). http://www.fasebj.org

An in vivo Interaction Network of DNA-Repair Proteins: A Snapshot at Double Strand Break Repair in Deinococcus radiodurans

“…PprA is known to preferentially bind dsDNA carrying strand breaks and stimulate end joining activities of ATP–/NAD-dependent DNA ligases . PprA is a multitasking protein that interacts with genome partitioning proteins ParA1 and ParA4, stimulate activity of DNA gyrase, and contributes to genome segregation and accurate cell division. ,, Thus, PprA protein may act on the intermediates generated by ESDSA and perform end-joining reaction.…”

“…51 PprA is a multitasking protein that interacts with genome partitioning proteins ParA1 and ParA4, stimulate activity of DNA gyrase, and contributes to genome segregation and accurate cell division. 18,52,53 Thus, PprA protein may act on the intermediates generated by ESDSA and perform end-joining reaction.…”

The Second Chromosome Promotes the Adaptation of the Genus Flammeovirga to Complex Environments

“…In addition to its efficient repair system, it also had chromosomal redundancy; that is, it had two chromosomes, and the extra genetic material protected the cell in two ways: when a large number of genomes existed, there were additional important site copies, thereby increasing the probability of cells surviving under radiation. Excess genetic information can also play a role in the repair of damaged fragments as reserved information ( 37 ). The bacteria of Flammeovirga all had a second chromosome.…”

Structural features and functional implications of proteins enabling the robustness of Deinococcus radiodurans

“…By mutagenesis screening using the hydroxylamine method and error-prone PCR, crystals of two mutant drPprA proteins were obtained successfully, which contain a dimer arrangement in the asymmetric unit ( Fig. 1 F) [55] . The most striking feature of drPprA is that it forms a face-to-face dimeric interface and displays a novel right-handed periodic screw assembly.…”