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Structure and Function of the T4 Spackle Protein Gp61.3

The bacteriophage T4 genome contains two genes that code for proteins with lysozyme activity—e and 5. Gene e encodes the well-known T4 lysozyme (commonly called T4L) that functions to break the peptidoglycan layer late in the infection cycle, which is required for liberating newly assembled phage pr...

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Autores principales: Kanamaru, Shuji, Uchida, Kazuya, Nemoto, Mai, Fraser, Alec, Arisaka, Fumio, Leiman, Petr G.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7650644/
https://www.ncbi.nlm.nih.gov/pubmed/32987925
http://dx.doi.org/10.3390/v12101070
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author Kanamaru, Shuji
Uchida, Kazuya
Nemoto, Mai
Fraser, Alec
Arisaka, Fumio
Leiman, Petr G.
author_facet Kanamaru, Shuji
Uchida, Kazuya
Nemoto, Mai
Fraser, Alec
Arisaka, Fumio
Leiman, Petr G.
author_sort Kanamaru, Shuji
collection PubMed
description The bacteriophage T4 genome contains two genes that code for proteins with lysozyme activity—e and 5. Gene e encodes the well-known T4 lysozyme (commonly called T4L) that functions to break the peptidoglycan layer late in the infection cycle, which is required for liberating newly assembled phage progeny. Gene product 5 (gp5) is the tail-associated lysozyme, a component of the phage particle. It forms a spike at the tip of the tail tube and functions to pierce the outer membrane of the Escherichia coli host cell after the phage has attached to the cell surface. Gp5 contains a T4L-like lysozyme domain that locally digests the peptidoglycan layer upon infection. The T4 Spackle protein (encoded by gene 61.3) has been thought to play a role in the inhibition of gp5 lysozyme activity and, as a consequence, in making cells infected by bacteriophage T4 resistant to later infection by T4 and closely related phages. Here we show that (1) gp61.3 is secreted into the periplasm where its N-terminal periplasm-targeting peptide is cleaved off; (2) gp61.3 forms a 1:1 complex with the lysozyme domain of gp5 (gp5Lys); (3) gp61.3 selectively inhibits the activity of gp5, but not that of T4L; (4) overexpression of gp5 causes cell lysis. We also report a crystal structure of the gp61.3-gp5Lys complex that demonstrates that unlike other known lysozyme inhibitors, gp61.3 does not interact with the active site cleft. Instead, it forms a “wall” that blocks access of an extended polysaccharide substrate to the cleft and, possibly, locks the enzyme in an “open-jaw”-like conformation making catalysis impossible.
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spelling pubmed-76506442020-11-10 Structure and Function of the T4 Spackle Protein Gp61.3 Kanamaru, Shuji Uchida, Kazuya Nemoto, Mai Fraser, Alec Arisaka, Fumio Leiman, Petr G. Viruses Article The bacteriophage T4 genome contains two genes that code for proteins with lysozyme activity—e and 5. Gene e encodes the well-known T4 lysozyme (commonly called T4L) that functions to break the peptidoglycan layer late in the infection cycle, which is required for liberating newly assembled phage progeny. Gene product 5 (gp5) is the tail-associated lysozyme, a component of the phage particle. It forms a spike at the tip of the tail tube and functions to pierce the outer membrane of the Escherichia coli host cell after the phage has attached to the cell surface. Gp5 contains a T4L-like lysozyme domain that locally digests the peptidoglycan layer upon infection. The T4 Spackle protein (encoded by gene 61.3) has been thought to play a role in the inhibition of gp5 lysozyme activity and, as a consequence, in making cells infected by bacteriophage T4 resistant to later infection by T4 and closely related phages. Here we show that (1) gp61.3 is secreted into the periplasm where its N-terminal periplasm-targeting peptide is cleaved off; (2) gp61.3 forms a 1:1 complex with the lysozyme domain of gp5 (gp5Lys); (3) gp61.3 selectively inhibits the activity of gp5, but not that of T4L; (4) overexpression of gp5 causes cell lysis. We also report a crystal structure of the gp61.3-gp5Lys complex that demonstrates that unlike other known lysozyme inhibitors, gp61.3 does not interact with the active site cleft. Instead, it forms a “wall” that blocks access of an extended polysaccharide substrate to the cleft and, possibly, locks the enzyme in an “open-jaw”-like conformation making catalysis impossible. MDPI 2020-09-24 /pmc/articles/PMC7650644/ /pubmed/32987925 http://dx.doi.org/10.3390/v12101070 Text en © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Kanamaru, Shuji
Uchida, Kazuya
Nemoto, Mai
Fraser, Alec
Arisaka, Fumio
Leiman, Petr G.
Structure and Function of the T4 Spackle Protein Gp61.3
title Structure and Function of the T4 Spackle Protein Gp61.3
title_full Structure and Function of the T4 Spackle Protein Gp61.3
title_fullStr Structure and Function of the T4 Spackle Protein Gp61.3
title_full_unstemmed Structure and Function of the T4 Spackle Protein Gp61.3
title_short Structure and Function of the T4 Spackle Protein Gp61.3
title_sort structure and function of the t4 spackle protein gp61.3
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7650644/
https://www.ncbi.nlm.nih.gov/pubmed/32987925
http://dx.doi.org/10.3390/v12101070
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