title: Secondary structure conversions of Mycobacterium tuberculosis ribonucleotide reductase protein R2 under varying pH and temperature conditions.
abstract: The structural properties of Mycobacterium tuberculosis (Mtb) ribonucleotide reductase R2 protein were studied under varying pH and temperature conditions by circular dichroism (CD) spectroscopy as well as dynamic light scattering (DLS). Under physiological conditions this protein has a high alpha-helical content, similar to the corresponding protein from other species, e.g. mouse. Decreasing the pH induced significant structure conversions. When pH was below 6.5 an aggregated structure was observed and reached a maximum at pH 4. The aggregated state of this protein was verified by DLS and was found to be rich in beta-structure. This amyloid-like structure transformed into a molten globule state with high temperature stability (between 25 and 80 degrees C) at pH below 3. The corresponding mouse protein R2 under similar conditions showed no evidence of an aggregated state around pH 4.
authors.affiliation: Department of Biochemistry and Biophysics, Stockholm University, Arrhenius Laboratories for Natural Sciences, Svante Arrhenius väg 10-12, S-10691 Stockholm, Sweden. erg54@cornell.edu
authors.forename: Elka R
authors.initials: ER
authors.lastname: Georgieva
authors.forename: Ana Julia
authors.initials: AJ
authors.lastname: Narvaez
authors.forename: Niklas
authors.initials: N
authors.lastname: Hedin
authors.forename: Astrid
authors.initials: A
authors.lastname: Gräslund
mesh_terms: D006863:Hydrogen-Ion Concentration; D009169:Mycobacterium tuberculosis / Q000201:enzymology*; D017510:Protein Folding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D012264:Ribonucleotide Reductases / Q000737:chemistry*; D013696:Temperature
chemical_list: D012264:Ribonucleotide Reductases