Bacterial alpha-2 macroglobulin (A2M) are located in the periplasm and may protect the cell by trapping external proteases through a covalent interaction with an activated thioester [1,2]. Macroglobulin (MG) beta sandwich domains appear to play a structural role. This entry represents bacterial MG2 (bMG2) domain which, with MG1, plays the role of a linker associating the main body of A2M to the bilayer [1-3].

1: Structure of protease-cleaved Escherichia coli alpha-2-macroglobulin reveals a putative mechanism of conformational activation for protease entrapment. Fyfe CD, Grinter R, Josts I, Mosbahi K, Roszak AW, Cogdell RJ, Wall DM, Burchmore RJ, Byron O, Walker D; Acta Crystallogr D Biol Crystallogr. 2015;71:1478-1486. PMID:26143919

2: Structure of a bacterial alpha2-macroglobulin reveals mimicry of eukaryotic innate immunity. Wong SG, Dessen A; Nat Commun. 2014;5:4917. PMID:25221932

3: Structural and functional insights into Escherichia coli alpha2-macroglobulin endopeptidase snap-trap inhibition. Garcia-Ferrer I, Arede P, Gomez-Blanco J, Luque D, Duquerroy S, Caston JR, Goulas T, Gomis-Ruth FX; Proc Natl Acad Sci U S A. 2015;112:8290-8295. PMID:26100869