Introduction to Protein ScienceArchitecture, Function, and Genomics

Arthur M. Lesk

Chapter 2: Genomics and ProteomicsP47-51

2008-11-10Jeong, Da-Geum, UST

Chapter2: Genomics and Proteomics - Protein evolution

1.Nucleic acid

2.Amino acid or expres-

sion pat-tern of protein

3.Activity of

the Pro-tein

Flow of Change----------------------------- Selectedadvantage

Disadvantage

Exception: Silent mutationEx: 3rd position in exons, untranslated regions

Simplest change to a protein is the substitution of a single amino acidThen, what is the effect on the protein structure and function?

Chapter2: Genomics and Proteomics - Protein evolution

1.No noticeable effect-> Robust protein to mutationEx) enzymes in closely related species

Substitution of (a single) amino acid

Other type of change

1 Insertion2 Deletion – cystic fibrosis3 Transpositions – degraded in the ER

Chapter2: Genomics and Proteomics - Protein evolution

How do proteins develop new functions?

(1)Divergence – progressive localized changes in sequence and structure-> initially to change in specificity -> ultimately to changes in the nature of the reaction catalysed(2) Recruitment – one protein is adapted(3)‘Mixing and matching’ of domains or modular evolution- large-scale structural changes- Individual domain-> gain of function, modified function, different processes.

Robustness of protein structure to mutations is a maintenance of structure in spite of the divergence of sequences during evolution