Structural highlights
Function
FIBER_BPSFV Non-covalently bound to the neck of the phage capsid and mediating attachment of the viral particle to host cell-surface polysaccharide. It displays endorhamnosidase enzymatic activity, hydrolyzing the alpha-1,3-O-glycosidic linkage between rhamnose and galactose of the O-antigen polysaccharide.[1] [2] [3]
Publication Abstract from PubMed
Sf6 is a bacterial virus that infects the human pathogen Shigella flexneri. Here, we describe the cryo-electron microscopy structure of the Sf6 tail machine before DNA ejection, which we determined at a 2.7-angstrom resolution. We built de novo structures of all tail components and resolved four symmetry-mismatched interfaces. Unexpectedly, we found that the tail exists in two conformations, rotated by ~6 degrees with respect to the capsid. The two tail conformers are identical in structure but differ solely in how the portal and head-to-tail adaptor carboxyl termini bond with the capsid at the fivefold vertex, similar to a diamond held over a five-pronged ring in two nonidentical states. Thus, in the mature Sf6 tail, the portal structure does not morph locally to accommodate the symmetry mismatch but exists in two energetic minima rotated by a discrete angle. We propose that the design principles of the Sf6 tail are conserved across P22-like Podoviridae.
High-resolution cryo-EM structure of the Shigella virus Sf6 genome delivery tail machine.,Li F, Hou CD, Yang R, Whitehead R 3rd, Teschke CM, Cingolani G Sci Adv. 2022 Dec 9;8(49):eadc9641. doi: 10.1126/sciadv.adc9641. Epub 2022 Dec 7. PMID:36475795[4]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Muller JJ, Barbirz S, Heinle K, Freiberg A, Seckler R, Heinemann U. An intersubunit active site between supercoiled parallel beta helices in the trimeric tailspike endorhamnosidase of Shigella flexneri Phage Sf6. Structure. 2008 May;16(5):766-75. PMID:18462681 doi:10.1016/j.str.2008.01.019
- ↑ Freiberg A, Morona R, Van den Bosch L, Jung C, Behlke J, Carlin N, Seckler R, Baxa U. The tailspike protein of Shigella phage Sf6. A structural homolog of Salmonella phage P22 tailspike protein without sequence similarity in the beta-helix domain. J Biol Chem. 2003 Jan 17;278(3):1542-8. PMID:12424253 doi:10.1074/jbc.M205294200
- ↑ Iwashita S, Kanegasaki S. Enzymic and molecular properties of base-plate parts of bacteriophage P22. Eur J Biochem. 1976 May 17;65(1):87-94. PMID:6284 doi:10.1111/j.1432-1033.1976.tb10392.x
- ↑ Li F, Hou CD, Yang R, Whitehead R 3rd, Teschke CM, Cingolani G. High-resolution cryo-EM structure of the Shigella virus Sf6 genome delivery tail machine. Sci Adv. 2022 Dec 9;8(49):eadc9641. doi: 10.1126/sciadv.adc9641. Epub 2022 Dec 7. PMID:36475795 doi:http://dx.doi.org/10.1126/sciadv.adc9641
