Membraneless channels sieve cations in ammonia-oxidizing marine archaea

Nitrosopumilus maritimus is an ammonia-oxidizing archaeon that is crucial to the global nitrogen cycle1, 2. A critical step for nitrogen oxidation is the entrapment of ammonium ions from a dilute marine environment at the cell surface and their subsequent channelling to the cell membrane of N. marit...

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Main Authors: von Kügelgen, A, Cassidy, CK, van Dorst, S, Pagani, LL, Batters, C, Ford, Z, Löwe, J, Alva, V, Stansfeld, PJ, Bharat, TAM
Format: Journal article
Language:English
Published: Nature Research 2024
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author von Kügelgen, A
Cassidy, CK
van Dorst, S
Pagani, LL
Batters, C
Ford, Z
Löwe, J
Alva, V
Stansfeld, PJ
Bharat, TAM
author_facet von Kügelgen, A
Cassidy, CK
van Dorst, S
Pagani, LL
Batters, C
Ford, Z
Löwe, J
Alva, V
Stansfeld, PJ
Bharat, TAM
author_sort von Kügelgen, A
collection OXFORD
description Nitrosopumilus maritimus is an ammonia-oxidizing archaeon that is crucial to the global nitrogen cycle1, 2. A critical step for nitrogen oxidation is the entrapment of ammonium ions from a dilute marine environment at the cell surface and their subsequent channelling to the cell membrane of N. maritimus. Here we elucidate the structure of the molecular machinery responsible for this process, comprising the surface layer (S-layer), using electron cryotomography and subtomogram averaging from cells. We supplemented our in situ structure of the ammonium-binding S-layer array with a single-particle electron cryomicroscopy structure, revealing detailed features of this immunoglobulin-rich and glycan-decorated S-layer. Biochemical analyses showed strong ammonium binding by the cell surface, which was lost after S-layer disassembly. Sensitive bioinformatic analyses identified similar S-layers in many ammonia-oxidizing archaea, with conserved sequence and structural characteristics. Moreover, molecular simulations and structure determination of ammonium-enriched specimens enabled us to examine the cation-binding properties of the S-layer, revealing how it concentrates ammonium ions on its cell-facing side, effectively acting as a multichannel sieve on the cell membrane. This in situ structural study illuminates the biogeochemically essential process of ammonium binding and channelling, common to many marine microorganisms that are fundamental to the nitrogen cycle.
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spelling oxford-uuid:09cccdda-6595-459d-b5b3-d133d4c5e3cd2024-06-05T20:18:39ZMembraneless channels sieve cations in ammonia-oxidizing marine archaeaJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:09cccdda-6595-459d-b5b3-d133d4c5e3cdEnglishJisc Publications RouterNature Research2024von Kügelgen, ACassidy, CKvan Dorst, SPagani, LLBatters, CFord, ZLöwe, JAlva, VStansfeld, PJBharat, TAMNitrosopumilus maritimus is an ammonia-oxidizing archaeon that is crucial to the global nitrogen cycle1, 2. A critical step for nitrogen oxidation is the entrapment of ammonium ions from a dilute marine environment at the cell surface and their subsequent channelling to the cell membrane of N. maritimus. Here we elucidate the structure of the molecular machinery responsible for this process, comprising the surface layer (S-layer), using electron cryotomography and subtomogram averaging from cells. We supplemented our in situ structure of the ammonium-binding S-layer array with a single-particle electron cryomicroscopy structure, revealing detailed features of this immunoglobulin-rich and glycan-decorated S-layer. Biochemical analyses showed strong ammonium binding by the cell surface, which was lost after S-layer disassembly. Sensitive bioinformatic analyses identified similar S-layers in many ammonia-oxidizing archaea, with conserved sequence and structural characteristics. Moreover, molecular simulations and structure determination of ammonium-enriched specimens enabled us to examine the cation-binding properties of the S-layer, revealing how it concentrates ammonium ions on its cell-facing side, effectively acting as a multichannel sieve on the cell membrane. This in situ structural study illuminates the biogeochemically essential process of ammonium binding and channelling, common to many marine microorganisms that are fundamental to the nitrogen cycle.
spellingShingle von Kügelgen, A
Cassidy, CK
van Dorst, S
Pagani, LL
Batters, C
Ford, Z
Löwe, J
Alva, V
Stansfeld, PJ
Bharat, TAM
Membraneless channels sieve cations in ammonia-oxidizing marine archaea
title Membraneless channels sieve cations in ammonia-oxidizing marine archaea
title_full Membraneless channels sieve cations in ammonia-oxidizing marine archaea
title_fullStr Membraneless channels sieve cations in ammonia-oxidizing marine archaea
title_full_unstemmed Membraneless channels sieve cations in ammonia-oxidizing marine archaea
title_short Membraneless channels sieve cations in ammonia-oxidizing marine archaea
title_sort membraneless channels sieve cations in ammonia oxidizing marine archaea
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