Investigations of Sso7d catalytic residues by NMR titration shifts and electrostatic calculations.

摘要: Sso7d is a small basic protein consisting of 62 amino acids isolated from the thermoacidophilic archeobacterium Sulfolobus solfataricus. The endowed with DNA binding properties, RNase activity, and capability rescuing aggregated proteins in presence ATP. In this study, electrostatic properties are investigated by using Poisson-Boltzmann calculation surface potential distribution following NMR spectroscopy proton chemical shift pH titration acidic residues. Although details catalytic mechanism still have to be defined, results experiments confirm possible involvement Glu35 as acceptor reaction, seen its abnormally high pK(a) value. calculations shifts suggest hydrogen bond between Tyr33, consequent rather rigid arrangement at these positions. Comparison T1 suggests that Tyr7 may good candidate for acting donor active site shown low phenolic approximately 9.3. Titration performed UpA, RNA dinucleotide model, showed residues affected interaction mainly located different region respect recognition, agreement found calculations.