Hypothetical proteins present during recovery phase of radiation resistant bacterium Deinococcus radiodurans are under purifying selection.
Deinococcus radiodurans has an unusual capacity to recover from intense doses of ionizing radiation. The DNA repair proteins of this organism play an important role in repairing the heavily damaged DNA by employing a novel mechanism of DNA double-strand break repair. An earlier report stated that genes of many of these repair proteins are under positive selection implying that these genes have a tendency to mutate, which in turn provides selective advantage to this bacterium. Several "hypothetical proteins" are also present during the recovery phase and some of them have also been shown for their roles in radiation resistance. Therefore, we tested the selection pressure on the genes encoding these poorly characterized proteins. Our results show that a number of "hypothetical proteins" present during the repair phase have structural adaptations compared to their orthologs and the genes encoding them as well as those for the DNA repair proteins present during this phase are under purifying selection. Evidence of purifying selection in these hypothetical proteins suggests that certain novel characteristics among these proteins are conserved and seem to be under functional constraints to perform important functions during recovery process after gamma radiation damage.
Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai, 400085, India, anubrata@barc.gov.in.
Anubrata D
AD
Das
Hari S
HS
Misra
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D019295:Computational Biology / Q000379:methods; D004249:DNA Damage / Q000528:radiation effects; D004260:DNA Repair; D034301:Deinococcus / Q000145:classification / Q000235:genetics* / Q000378:metabolism / Q000528:radiation effects; D005720:Gamma Rays / Q000009:adverse effects; D015964:Gene Expression Regulation, Bacterial / Q000528:radiation effects; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010802:Phylogeny; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D011836:Radiation Tolerance / Q000235:genetics*; D012641:Selection, Genetic; D016415:Sequence Alignment; D059467:Transcriptome
D001426:Bacterial Proteins