Fagagnini, A.; Garavís, M.; Gómez-Pinto, I.; Fasoli, S.; Gotte, G.; Laurents, D.V. NMR Characterization of Angiogenin Variants and tRNAAla Products Impacting Aberrant Protein Oligomerization. Int. J. Mol. Sci.2021, 22, 1439.
Fagagnini, A.; Garavís, M.; Gómez-Pinto, I.; Fasoli, S.; Gotte, G.; Laurents, D.V. NMR Characterization of Angiogenin Variants and tRNAAla Products Impacting Aberrant Protein Oligomerization. Int. J. Mol. Sci. 2021, 22, 1439.
Protein oligomerzation is key to countless physiological processes, but also to abnormal amyloid conformations implicated in over 25 mortal human diseases. Angiogenin (h-ANG), a ribonuclease A family member, produces RNA fragments that regulate ribosome formation, the creation of new blood vessels and stress granule function. Too little h-ANG activity leads abnormal protein oligomerization resulting in Amyotrophic Lateral Sclerosis (ALS) or Parkinson’s disease. While a score of disease linked h-ANG mutants has been studied by X-ray diffraction, some elude crystallization. There is also debate regarding the structure that RNA fragments adopt after cleavage by h-ANG. Here, to better understand the beginning of the process that leads to aberrant protein oligomerization, the solution secondary structure and residue-level dynamics of WT h-ANG and two mutants: H13A and R121C, are characterized by multidimensional heteronuclear NMR spectroscopy under near physiological conditions. All three variants are found to adopt well folded and highly rigid structures in solution, although the elements of secondary structure are somewhat shorter than those observed in cystallography studies. R121C alters the environment of nearby residues only. By constrast, the mutation H13A affects local residues as well as nearby active site residues residues K41 and H119. The conformation characterization by CD and 1D 1H NMR spectroscopies of tRNAAla before and after h-ANG cleavage reveals a retention of most duplex structure and little or no G-quadruplex formation.
Protein Oligomerization; Angiogenin (h-ANG); tRNA; ALS; stress granules; NMR spectroscopy
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