Members of the enolase mechanistically diverse superfamily catalyze a wide variety of chemical reactions that are related by a common mechanistic feature, the abstraction of a proton adjacent to a carboxylate group. Recent investigations into the function and mechanism of the phosphosulfolactate synthase encoded by the ComA gene in Methanococcus jannaschii have suggested that ComA, which cataly...

In this paper an analysis of 175 currently sequenced transport proteins that comprise the amino acid/polyamine/organocation (APC) superfamily is reported. Members of this superfamily fall into 10 well-defined families that are either prokaryote specific, eukaryote specific or ubiquitous. Most of these proteins exhibit 12 probable transmembrane spanners (TMSs), but members of two of these famili...

The amidohydrolase superfamily is a structure-based cluster of enzymes that contain a sturdy and versatile triosephosphate isomerase (TIM)-like (b/a)8-barrel fold embracing the catalytic active site. To date, the amidohydrolase superfamily has grown into one of the largest families of enzymes, with tens of thousand of members catalysing a wide range of hydrolytic and nonhydrolytic metabolic rea...

Structural and biochemical constraints force some segments of proteins to evolve more slowly than others, often allowing identification of conserved structural or sequence motifs that can be associated with substrate binding properties, chemical mechanisms, and molecular functions. We have assessed the functional and structural constraints imposed by cofactors on the evolution of new functions ...

The ASIC channels constitute a subfamily within the larger ENaC superfamily. Despite the fact that the ASICs share only about 20-25% identity with the ENaC channels they display all the characteristics of the superfamily, which are, two transmembrane spanning domains, a large extracellular domain and short intracellular N and C termini. The functional channel of the superfamily is composed of 4...