Identification of a binding pocket of letermovir in the terminase subunit pUL56 of human cytomegalovirus

Abstract A key step in replication of human cytomegalovirus (HCMV) is the generation and packaging of unit-length genomes into preformed capsids. The enzymes involved in this process are viral terminases. The HCMV terminase consists of two subunits, the ATPase pUL56 and the nuclease pUL89. A potenti...

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Main Authors: Lukas M. Kmetsch, Hans Tietze, Elke Bogner
Format: Article
Language:English
Published: Nature Portfolio 2025-03-01
Series:Scientific Reports
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Online Access:https://doi.org/10.1038/s41598-025-94809-1
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author Lukas M. Kmetsch
Hans Tietze
Elke Bogner
author_facet Lukas M. Kmetsch
Hans Tietze
Elke Bogner
author_sort Lukas M. Kmetsch
collection DOAJ
description Abstract A key step in replication of human cytomegalovirus (HCMV) is the generation and packaging of unit-length genomes into preformed capsids. The enzymes involved in this process are viral terminases. The HCMV terminase consists of two subunits, the ATPase pUL56 and the nuclease pUL89. A potential third component, pUL51, has been proposed. Letermovir is the first terminase inhibitor available for HCMV prophylaxis to allogenic hematopoietic stem cell recipients. However, mutations in the HCMV terminase subunit pUL56 and, to a lesser extent, in pUL89 or pUL51 lead to resistance. Here we focused on the drug target area in the terminase subunit pUL56. To gain further structural insights into the putative binding site of letermovir, in silico analysis of the structure was performed using Phyre2 and SwissDock. For our analysis, we used three of the most frequent mutations during letermovir treatment, C325F, C325Y and C325W. We demonstrated that all variants have a pronounced cavity reduction, leading to the letermovir binding conformations being “pushed-out” of the binding pocket. This results in a changed distribution of the Gibbs free binding energy. To circumvent the absolute resistance of C325 mutations a further modification of letermovir might solve the problem and leads to optimizing drug targeting capacity.
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spelling doaj-art-896dec47f6c548b4bcd1bb2155405c202025-08-20T02:10:16ZengNature PortfolioScientific Reports2045-23222025-03-0115111110.1038/s41598-025-94809-1Identification of a binding pocket of letermovir in the terminase subunit pUL56 of human cytomegalovirusLukas M. Kmetsch0Hans Tietze1Elke Bogner2Institute of Virology, Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität Zu BerlinInstitute of Virology, Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität Zu BerlinInstitute of Virology, Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität Zu BerlinAbstract A key step in replication of human cytomegalovirus (HCMV) is the generation and packaging of unit-length genomes into preformed capsids. The enzymes involved in this process are viral terminases. The HCMV terminase consists of two subunits, the ATPase pUL56 and the nuclease pUL89. A potential third component, pUL51, has been proposed. Letermovir is the first terminase inhibitor available for HCMV prophylaxis to allogenic hematopoietic stem cell recipients. However, mutations in the HCMV terminase subunit pUL56 and, to a lesser extent, in pUL89 or pUL51 lead to resistance. Here we focused on the drug target area in the terminase subunit pUL56. To gain further structural insights into the putative binding site of letermovir, in silico analysis of the structure was performed using Phyre2 and SwissDock. For our analysis, we used three of the most frequent mutations during letermovir treatment, C325F, C325Y and C325W. We demonstrated that all variants have a pronounced cavity reduction, leading to the letermovir binding conformations being “pushed-out” of the binding pocket. This results in a changed distribution of the Gibbs free binding energy. To circumvent the absolute resistance of C325 mutations a further modification of letermovir might solve the problem and leads to optimizing drug targeting capacity.https://doi.org/10.1038/s41598-025-94809-1Human cytomegalovirusTerminaseLetermovirBinding pocket
spellingShingle Lukas M. Kmetsch
Hans Tietze
Elke Bogner
Identification of a binding pocket of letermovir in the terminase subunit pUL56 of human cytomegalovirus
Scientific Reports
Human cytomegalovirus
Terminase
Letermovir
Binding pocket
title Identification of a binding pocket of letermovir in the terminase subunit pUL56 of human cytomegalovirus
title_full Identification of a binding pocket of letermovir in the terminase subunit pUL56 of human cytomegalovirus
title_fullStr Identification of a binding pocket of letermovir in the terminase subunit pUL56 of human cytomegalovirus
title_full_unstemmed Identification of a binding pocket of letermovir in the terminase subunit pUL56 of human cytomegalovirus
title_short Identification of a binding pocket of letermovir in the terminase subunit pUL56 of human cytomegalovirus
title_sort identification of a binding pocket of letermovir in the terminase subunit pul56 of human cytomegalovirus
topic Human cytomegalovirus
Terminase
Letermovir
Binding pocket
url https://doi.org/10.1038/s41598-025-94809-1
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AT elkebogner identificationofabindingpocketofletermovirintheterminasesubunitpul56ofhumancytomegalovirus