PROSITE documentation PDOC51255

ADP-dependent kinase (ADPK) domain profile

Although ATP is the most common phosphoryl group donor for kinases, certain hyperthermophilic archaea, such as Thermococcus litoralis and Pyrococcus furiosus, utilize unusual ADP-dependent glucokinases (ADPGKs) and phosphofructokinases (ADPPKKs) in their glycolytic pathways [1,2,3]. ADPGKs and ADPPFKs exhibit significant similarity, and form an ADP-dependent kinase (ADPK) family, which was tentatively named the PFKC family [4]. A ~460-residue ADPK domain is also found in a bifunctional ADP-dependent gluco/phosphofructo-kinase (ADP-GK/PFK) from Methanococcus jannaschii as well as in homologous hypothetical proteins present in several eukaryotes [5].

The whole structure of the ADPK domain can be divided into large and small α/β subdomains (see <PDB:1GC5; A>). The larger subdomain, which carries the ADP binding site, consists of a twisted 12-stranded β sheet flanked on both faces by 13 α helices and three 3(10) helices, forming an α/β 3-layer sandwich. The smaller subdomain, which covers the active site, forms an α/β two-layer structure containing 5 β strands and four α helices. The ADP molecule is buried in a shallow pocket in the large subdomain. The binding of substrate sugar induces a structural change, the small domain closing to form a complete substrate sugar binding site [1,2,3].

The profile we developed covers the entire ADPK domain.