This is the linker domain found in Formylglycinamide ribonucleotide amidotransferase (FGAR-AT), also known as Phosphoribosylformylglycinamidine synthase (EC:6.3.5.3), PurL and formylglycinamidine ribonucleotide (FGAM) synthase. This enzyme catalyzes the ATP-dependent conversion of formylglycinamide ribonucleotide (FGAR) and glutamine to formylglycinamidine ribonucleotide (FGAM), ADP, Pi, and glutamate in the fourth step of the purine biosynthetic pathway. The structure analysis of Salmonella typhimurium FGAR-AT reveals that this linker domain is made up of a long hydrophilic belt with an extended conformation [4].

1: Crystal structure of phosphoribosylformylglycinamidine synthase II (smPurL) from Thermotoga maritima at 2.15 A resolution. Mathews II, Krishna SS, Schwarzenbacher R, McMullan D, Abdubek P, Ambing E, Canaves JM, Chiu HJ, Deacon AM, DiDonato M, Elsliger MA, Godzik A, Grittini C, Grzechnik SK, Hale J, Hampton E, Han GW, Haugen J, Jaroszewski L, Klock HE, Koesema E, Kreusch A, Kuhn P, Lesley SA, Levin I, Miller MD, Moy K, Nigoghossian E, Paulsen J, Quijano K, Reyes R, Spraggon G, Stevens RC, van den Bedem H, Velasquez J, White A, Wolf G, Xu Q, Hodgson KO, Wooley J, Wilson IA; Proteins. 2006;63:1106-1111. PMID:16544324

2: Complexed structures of formylglycinamide ribonucleotide amidotransferase from Thermotoga maritima describe a novel ATP binding protein superfamily. Morar M, Anand R, Hoskins AA, Stubbe J, Ealick SE; Biochemistry. 2006;45:14880-14895. PMID:17154526

3: Formylglycinamide ribonucleotide amidotransferase from Thermotoga maritima: structural insights into complex formation. Morar M, Hoskins AA, Stubbe J, Ealick SE; Biochemistry. 2008;47:7816-7830. PMID:18597481

4: Domain organization of Salmonella typhimurium formylglycinamide ribonucleotide amidotransferase revealed by X-ray crystallography. Anand R, Hoskins AA, Stubbe J, Ealick SE; Biochemistry. 2004;43:10328-10342. PMID:15301531

5: Formylglycinamide ribonucleotide amidotransferase from Salmonella typhimurium: role of ATP complexation and the glutaminase domain in catalytic coupling. Tanwar AS, Morar M, Panjikar S, Anand R; Acta Crystallogr D Biol Crystallogr. 2012;68:627-636. PMID:22683785

6: Importance of hydrophobic cavities in allosteric regulation of formylglycinamide synthetase: insight from xenon trapping and statistical coupling analysis. Tanwar AS, Goyal VD, Choudhary D, Panjikar S, Anand R; PLoS One. 2013;8:e77781. PMID:24223728

7: Structure of N-formylglycinamide ribonucleotide amidotransferase II (PurL) from Thermus thermophilus HB8. Suzuki S, Yanai H, Kanagawa M, Tamura S, Watanabe Y, Fuse K, Baba S, Sampei G, Kawai G; Acta Crystallogr Sect F Struct Biol Cryst Commun. 2012;68:14-19. PMID:22232163