Conservative mutation

Conservative mutations are mutations that change an amino acid to a different amino acid with similar biochemical properties (e.g. charge, hydrophobicity and size).

Description

A sequence alignment, produced by ClustalO, of mammalian histone proteins.
Sequences are the amino acids for residues 120-180 of the proteins. Residues that are conserved across all sequences are highlighted in grey. Below the protein sequences is a key denoting conserved sequence (*), conservative mutations (:), semi-conservative mutations (.), and non-conservative mutations ( ).^[1]

There are 20 naturally occurring amino acids, however some of these share similar characteristics. For example, leucine and isoleucine are both aliphatic, branched hydrophobes. Similarly, aspartic acid and glutamic acid are both small, negatively charged residues. Conservative mutations in proteins often have a smaller effect on function than non-conservative mutations. The reduced effect of conservative mutations on function can also be seen in the occurrence of different mutations in nature. Non-conservative mutations between proteins are far more likely to be removed by natural selection due to their deleterious effects.

Although there are many ways to classify amino acids, they are often sorted into six main groups on the basis of their structure and the general chemical characteristics of their R groups.

See also

• Segregating site
• Ultra-conserved element
• Sequence alignment
• Sequence alignment software
• ClustalW

References