Interspecific adaptation by binary choice at de novo polyomavirus T antigen site through accelerated codon-constrained Val-Ala toggling within an intrinsically disordered region.

ABSTRACT: It is common knowledge that conserved residues evolve slowly. We challenge generality of this central tenet of molecular biology by describing the fast evolution of a conserved nucleotide position that is located in the overlap of two open reading frames (ORFs) of polyomaviruses. The de novo ORF is expressed through either the ALTO protein or the Middle T antigen (MT/ALTO), while the ancestral ORF encodes the N-terminal domain of helicase-containing Large T (LT) antigen. In the latter domain the conserved Cys codon of the LXCXE pRB-binding motif constrains codon evolution in the overlapping MT/ALTO ORF to a binary choice between Val and Ala codons, termed here as codon-constrained Val-Ala (COCO-VA) toggling. We found the rate of COCO-VA toggling to approach the speciation rate and to be si

SUBMITTER: Lauber C 

PROVIDER: S-EPMC4446436 | biostudies-literature | 2015 May

REPOSITORIES: biostudies-literature