Which one of the following can be homologous substitution for isoleucine in a protein in sequence?: (A) Methionine, (B) Aspartic acid, (C) Valine, (D) Arginine
Answer is C. Ans. C. ValineConservative SubstitutionOne amino acid replaced by another amino acid of similar characteristicsExamples of homologous substitution is shown in the given table below.Hydrophilic, AcidicAspGlu Hydrophilic, BasicHisArgLys Polar, UnchargedSerThrGlnAsn HydrophobicAlaPheLeuIleValProNonconservative (Nonhomologous) SubstitutionOne amino acid replaced by another amino acid of different characteristics