Study of the effect of pH on the induction of alpha-helix of the intrinsically disordered region of the viral phosphoprotein responsible for binding to the transcriptional termination factor M2-1 of the human Respiratory Syncytial Virus

Abstract

Human Respiratory Syncytial Virus (hRSV) is one of the most common pathological agents of acute respiratory infections in newborns, children, and elderly, being responsible for diseases such as bronchiolitis and pneumonia. In the replication cycle of this virus, the interaction between the M2-1 anti-termination factor and phosphoprotein P is important for the success of viral transcription. The M2-1/P interaction occurs between the globular domain of M2-1 (dgM2-1) and the intrinsically disordered region (IDR) of residues 90-110 of P (P90-110). The present project aims to characterize the effect of pH on the induction of the alpha-helix of the IDR P90-110 responsible for the interaction with the M2-1 protein of hRSV. The formation of alpha-helix will be induced by titrations of dgM2-1 at pH 7 and 2,2,2-trifluorethanol under different pH conditions (from 3 to 10), and this formation will be investigated by the techniques of Circular Dichroism and Nuclear Magnetic Resonance. Studies in the literature show that an important factor to control the folding of an IDR is the relationship between the amount and distribution of charged amino acid residues in its primary sequence. Thus, carrying out studies that molecularly detail the importance of charged residues for the folding of IDR P90-110, can consequently lead to a better understanding of the interaction process between M2-1 and the viral phosphoprotein. Therefore, the results of the present proposal can help in the development of a new strategy to combat hRSV, which would have as a molecular target the blocking of the M2-1/P interaction by P90-110 mimetic peptides.