Adaptive threonine increase in transmembrane regions of mitochondrial proteins in higher primates.

ABSTRACT:

Background

The mitochondrial (mt) gene tree of placental mammals reveals a very strong acceleration of the amino acid (AA) replacement rate and a change in AA compositional bias in the lineage leading to the higher primates (simians), in contrast to the nuclear gene tree. Whether this acceleration and compositional bias were caused by adaptive evolution at the AA level or directional mutation pressure at the DNA level has been vigorously debated.

Methodology/principal findings

Our phylogenetic analysis indicates that the rate acceleration in the simian lineage is accompanied by a marked increase in threonine (Thr) residues in the transmembrane helix regions of mt DNA-encoded proteins. This Thr increase involved the replacement of hydrophobic AAs in the membrane interior. Eve

SUBMITTER: Kitazoe Y 

PROVIDER: S-EPMC2553178 | biostudies-literature | 2008 Oct

REPOSITORIES: biostudies-literature