4ziu

Structural highlights

Function

A2MG_ECOLI Protects the bacterial cell from host peptidases (PubMed:18697741, PubMed:26143919, PubMed:26100869). Acts by a 'trapping' mechanism. Cleavage of the bait-region domain by host peptidases leads to a global conformational change, which results in entrapment of the host peptidase and activation of the thioester bond that covalently binds the attacking host peptidase (PubMed:26143919, PubMed:26100869). Trapped peptidases are still active except against very large substrates (PubMed:26100869). May protect the entire periplam, including the lipoproteins anchored to the periplasmic side of the outer membrane, against intruding endopeptidases (PubMed:26100869).^{[1] [2] [3]}

References

1. ↑ Doan N, Gettins PG. alpha-Macroglobulins are present in some gram-negative bacteria: characterization of the alpha2-macroglobulin from Escherichia coli. J Biol Chem. 2008 Oct 17;283(42):28747-56. PMID:18697741 doi:10.1074/jbc.M803127200
2. ↑ Garcia-Ferrer I, Arede P, Gomez-Blanco J, Luque D, Duquerroy S, Caston JR, Goulas T, Gomis-Ruth FX. Structural and functional insights into Escherichia coli alpha2-macroglobulin endopeptidase snap-trap inhibition. Proc Natl Acad Sci U S A. 2015 Jun 22. pii: 201506538. PMID:26100869 doi:http://dx.doi.org/10.1073/pnas.1506538112
3. ↑ Fyfe CD, Grinter R, Josts I, Mosbahi K, Roszak AW, Cogdell RJ, Wall DM, Burchmore RJ, Byron O, Walker D. Structure of protease-cleaved Escherichia coli alpha-2-macroglobulin reveals a putative mechanism of conformational activation for protease entrapment. Acta Crystallogr D Biol Crystallogr. 2015 Jul 1;71(Pt 7):1478-86. doi:, 10.1107/S1399004715008548. Epub 2015 Jun 30. PMID:26143919 doi:http://dx.doi.org/10.1107/S1399004715008548