The Conformation of the N-Terminal Tails of Deinococcus grandis Dps Is Modulated by the Ionic Strength.
João P L GuerraClement E BlanchetBruno J C VieiraAna V AlmeidaJoao Carlos WaerenborghNykola C JonesSøren Vrønning HoffmannPedro TavaresAlice S PereiraPublished in: International journal of molecular sciences (2022)
DNA-binding proteins from starved cells (Dps) are homododecameric nanocages, with N- and C-terminal tail extensions of variable length and amino acid composition. They accumulate iron in the form of a ferrihydrite mineral core and are capable of binding to and compacting DNA, forming low- and high-order condensates. This dual activity is designed to protect DNA from oxidative stress, resulting from Fenton chemistry or radiation exposure. In most Dps proteins, the DNA-binding properties stem from the N-terminal tail extensions. We explored the structural characteristics of a Dps from Deinococcus grandis that exhibits an atypically long N-terminal tail composed of 52 residues and probed the impact of the ionic strength on protein conformation using size exclusion chromatography, dynamic light scattering, synchrotron radiation circular dichroism and small-angle X-ray scattering. A novel high-spin ferrous iron-binding site was identified in the N-terminal tails, using Mössbauer spectroscopy. Our data reveals that the N-terminal tails are structurally dynamic and alter between compact and extended conformations, depending on the ionic strength of the buffer. This prompts the search for other physiologically relevant modulators of tail conformation and hints that the DNA-binding properties of Dps proteins may be affected by external factors.
Keyphrases
- dna binding
- single molecule
- circulating tumor
- transcription factor
- molecular dynamics simulations
- amino acid
- cell free
- high resolution
- oxidative stress
- induced apoptosis
- solid state
- ionic liquid
- mass spectrometry
- crystal structure
- small molecule
- cell cycle arrest
- wastewater treatment
- high speed
- room temperature
- hydrogen peroxide
- computed tomography
- magnetic resonance imaging
- machine learning
- protein protein
- signaling pathway
- high performance liquid chromatography
- iron deficiency
- ischemia reperfusion injury
- diabetic rats
- dual energy
- artificial intelligence
- ms ms