Question

Yours truly collected the following HSQC spectra of RNase P protein (Henkels et al. (2001). Biochemistry 40: 2777), whose crystal structure can be found in the protein database (pdb code 1A6F). Pure RNase P protein in the absence of sulfate (a other anions, as well as its natural binding partner P RNA) is shown in the top spectrum, while the bottom spectrum contained pure RNase P protein with 20mM sulfate; both spectra were collected at pH 7. Which of the two HSQC spectra is consistent with the conformation of RNase P protein determined by x-ray crystallography? Please explain.

Answer 1

105.0 110.0 The folded state of RNAase P protein with HSQC spectrum resonances at p 115.0 120.0 125.0 These are extra peaks appear under buffer conditions at pH 7 130.0 10.00 9.50 9.00 8.50 8.00 7.50 7.00 6.50 H (ppm) Answer: The bottom graph is consitent with HSQC spectra & has conformation of RNase P protein. X-ray crystallography: Pure RNase P protein with 20mM sulfate treatment at pH 7 have revealed that the extra peak intensity has decreased result in HSQC spectrum generation with higher folded P protein resonances (with histidine residues) compared to unfolded state