The effects of codon usage on the formation of secondary structures of nucleocapsid protein of peste des petits ruminants virus.

The nucleocapsid (N) protein of peste des petits ruminants virus (PPRV) with a conserved amino acid usage pattern plays an important role in viral replication. The primary objective of this study was to estimate roles of synonymous codon usages of PPRV N gene and tRNA abundances of host in the formation of secondary structure of N protein. The potential effects of synonymous codon usages of N gene and tRNA abundances of host on shaping different folding units (α-helix, β-strand and the coil) in N protein were estimated, based on the information about the modeling secondary structure of PPRV N protein. The synonymous codon usage bias was found in different folding units in PPRV N protein. To better understand the role of translation speed caused by variant tRNA abundances in shaping the specific folding unit in N protein, we modeled the changing trends of tRNA abundance at the transition boundaries from one folding unit to another folding unit (β-strand → coil, coil → β-strand, α-helix → coil, coil → α-helix). The obvious fluctuations of tRNA abundance were identified at the two transition boundaries (β-strand → coil and coil → β-strand) in PPRV N protein. Our findings suggested that viral synonymous codon usage bias and cellular tRNA abundance variation might have potential effects on the formation of secondary structure of PPRV N protein.