6xc1 | pdb_00006xc1
Crystal structure of bacteriophage T4 spackle and lysozyme in orthorhombic form
Structural highlights
FunctionNEEDL_BPT4 Tail-associated lysozyme of the baseplate hub that is essential for localized hydrolysis of bacterial cell wall necessary for viral DNA injection. The needle-like gp5 protein punctures the outer cell membrane and then digests the peptidoglycan cell wall in the periplasmic space. Involved in the tail assembly.[1] [2] Publication Abstract from PubMedA bacterial cell infected with T4 phage rapidly establishes resistance against further infections by the same or closely related T-even-type bacteriophages - a phenomenon called superinfection exclusion. Here we show that one of the T4 early gene products and a periplasmic protein, Spackle, forms a stoichiometric complex with the lysozyme domain of T4 tail spike protein gp5 and potently inhibits its activity. Crystal structure of the Spackle-gp5 lysozyme complex shows that Spackle binds to a horseshoe-shaped basic patch surrounding the oligosaccharide-binding cleft and induces an allosteric conformational change of the active site. In contrast, Spackle does not appreciably inhibit the lysozyme activity of cytoplasmic T4 endolysin responsible for cell lysis to release progeny phage particles at the final step of the lytic cycle. Our work reveals a unique mode of inhibition for lysozymes, a widespread class of enzymes in biology, and provides a mechanistic understanding of the T4 bacteriophage superinfection exclusion. Structural basis of superinfection exclusion by bacteriophage T4 Spackle.,Shi K, Oakland JT, Kurniawan F, Moeller NH, Banerjee S, Aihara H Commun Biol. 2020 Nov 19;3(1):691. doi: 10.1038/s42003-020-01412-3. PMID:33214665[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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