Extreme variations in the ratios of non‐synonymous to synonymous nucleotide substitution rates in signal peptide evolution

FEBS Letters

de la Hoz, Pilar Sanchez¹  Castagnaro, Atilio¹  Maraña, Carmen¹  García-Olmedo, Francisco¹  Carbonero, Pilar¹  Garcia-Maroto, Federico¹ 

[1] Bioquimica Biología Molecular, E.T.S. Ingenieras Arónomos-UPM, E-28040 Madrid, Spain

关键词: α-Amylase/trypsin inhibitor;    Thaumatin II;    Thionin;    Plastocyanin;    Signal peptide evolution;   

DOI  :  10.1016/0014-5793(91)80017-W

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Nucleotide sequences encoding signal peptidcs from the precursors of α-amylase/trypsin inhibitors from cereals are homologous to those corresponding to the precursors of thaumatin II and of plastocyanins. Non-synonymous (K _A) and synonymous (K _S) rates of nucleotide substitutions have been calculated for all possible binary combinations. Extreme variation in K _A/K _S ratios has been observed, from the 0.167 average found within the plastocyanin family to an average of 1.90 calculated for the inhibitors/thaumatin II transition. A similar calculation has been carried out for the signal peptide sequences of thionins. which are unrelated to those of the α-amylase trypsin inhibitor family, and an average K _A/K _S of 0.12 has been obtained. This variation can be largely explained in terms of an empirical index of stability related to amino acid composition and seems to be independent of functional constraints.

【 授权许可】

Unknown