| Title |
Salt resistance mechanism of halotolerant / halophilic prokaryotic DNases and halotolerance induction for bovine DNaseI / |
| Translation of Title |
Prokariotinių DNazės I homologų pakantumo druskingumui / halofiliškumo mechanizmai bei jaučio DNazės I atsparumo joninei jėgai didinimas. |
| Authors |
Alzbutas, Gediminas |
| Full Text |
|
| Pages |
46 |
| Keywords [eng] |
DNase ; HhH motif, DNA binding domain ; halophile ; adaptation |
| Abstract [eng] |
Analysis of the sequence data revealed that many prokaryotic DNaseI-like nucleases from halotolerant / halophilic species are multi domain proteins. This fact led to a hypothesis that in some cases a fusion of an additional domain to the DNase domain was the key factor in evolution that enabled the activity of prokaryotic DNases at high ionic strength. In this study the hypothesis was experimentally proved by analysing halo- tolerance of one DNase from Thioalkalivibrio sp. K90mix (DNaseTA) and its mutants. DNaseTA is comprised of two domains: one domain is DNaseI-like and the other is a DNA-binding domain comprising two HhH (helix-hairpin- helix) motifs. It was decided to mimic in vitro the evolutionary step that created the natural fusion. The research revealed that this domain originated from ComEA/ComE proteins (DNA receptor of bacterial competence system) and through the course of evolution was fused with the DNaseI-like domain. In this study the domain organization of DNaseTA was mimicked by creating two fusion proteins comprising bovine DNaseI and a DNA-binding domain. Both fusions with additional DNA binding domains were demonstrated to be more salt tolerant than bovine DNaseI, albeit to different extent. Molecular modelling data suggested that differences in tolerance for high ionic strength between the two created DNaseI fusions could be due to differences in hydrogen bonding between the fused domains and DNA and different ability to transfer monovalent cations to solvent during DNA-protein complex formation. |
| Dissertation Institution |
Vilniaus universitetas. |
| Type |
Summaries of doctoral thesis |
| Language |
English |
| Publication date |
2016 |
