This domain is found at the C terminus of Glucokinase regulatory protein (GKRP) from animals and N-acetylmuramic acid 6-phosphate etherase (MurQ) from bacteria. GKRP binds Glucokinase (GK) mainly through hydrophobic interactions, functioning as an allosteric switch in blood glucose control by the liver [1]. GKRP is trilobal in shape, consisting of two topologically identical sugar isomerase (SIS) domains (Pfam:PF01380 and Pfam:PF13580) capped by an alpha helical C-terminal domain (this entry). The Lid domain consists of a bundle of seven alpha helices with a core that shows a UBA-like fold [2]. MurQ, which also shows a SIS domain, plays a key role in the peptidoglycane recycling pathway. Its crystal structure shows each monomer have an alpha-beta-alpha sandwich fold commonly found in regulatory proteins controlling the expression of genes involved in the synthesis of phosphosugars. The C-terminal domain of this protein (this entry) is comprised of five alpha helices [4].

1: Molecular basis for the role of glucokinase regulatory protein as the allosteric switch for glucokinase. Choi JM, Seo MH, Kyeong HH, Kim E, Kim HS; Proc Natl Acad Sci U S A. 2013;110:10171-10176. PMID:23733961

2: Crystal structure of glucokinase regulatory protein. Pautsch A, Stadler N, Lohle A, Rist W, Berg A, Glocker L, Nar H, Reinert D, Lenter M, Heckel A, Schnapp G, Kauschke SG; Biochemistry. 2013;52:3523-3531. PMID:23621087

3: Structural basis for regulation of human glucokinase by glucokinase regulatory protein. Beck T, Miller BG; Biochemistry. 2013;52:6232-6239. PMID:23957911

4: Antidiabetic effects of glucokinase regulatory protein small-molecule disruptors. Lloyd DJ, St Jean DJ Jr, Kurzeja RJ, Wahl RC, Michelsen K, Cupples R, Chen M, Wu J, Sivits G, Helmering J, Komorowski R, Ashton KS, Pennington LD, Fotsch C, Vazir M, Chen K, Chmait S, Zhang J, Liu L, Norman MH, Andrews KL, Bartberger MD, Van G, Galbreath EJ, Vonderfecht SL, Wang M, Jordan SR, Veniant MM, Hale C; Nature. 2013;504:437-440. PMID:24226772

5: Structure of MurNAc 6-phosphate hydrolase (MurQ) from Haemophilus influenzae with a bound inhibitor. Hadi T, Hazra S, Tanner ME, Blanchard JS; Biochemistry. 2013;52:9358-9366. PMID:24251551