GAPES3 (GAmmaproteobacterial PEriplasmic Sensor) domain is a periplasmic sensor domain found in diguanylate cyclases/phosphodiesterases, including the c-di-GMP phosphodiesterases PdeK (YhjK) of Escherichia coli and HmsP of Yersinia pestis [1,2,3].

1: The phosphodiesterase activity of the HmsP EAL domain is required for negative regulation of biofilm formation in Yersinia pestis. Bobrov AG, Kirillina O, Perry RD; FEMS Microbiol Lett. 2005;247:123-130. PMID:15935569

2: Systematic analysis of cyclic di-GMP signalling enzymes and their role in biofilm formation and virulence in Yersinia pestis. Bobrov AG, Kirillina O, Ryjenkov DA, Waters CM, Price PA, Fetherston JD, Mack D, Goldman WE, Gomelsky M, Perry RD; Mol Microbiol. 2011;79:533-551. PMID:21219468

3: Systematic Nomenclature for GGDEF and EAL Domain-Containing Cyclic Di-GMP Turnover Proteins of Escherichia coli. Hengge R, Galperin MY, Ghigo JM, Gomelsky M, Green J, Hughes KT, Jenal U, Landini P; J Bacteriol. 2015;198:7-11. PMID:26148715