Figure 1.

The evolutionary history of the mal genes in the Thermococcales. malE/mdxE encode the substrate binding proteins (SBPs), malF/mdxF and malG/mdxG encode membrane spanning proteins (MSPs) also known as permease subunits, and malK/mdxK encode ATP binding proteins (ABP) containing an ATP binding cassette (ABC). Subscript An denotes ancestral genes.