Cargando…
Insight into the Assembly Properties and Functional Organisation of the Magnetotactic Bacterial Actin-like Homolog, MamK
Magnetotactic bacteria (MTB) synthesize magnetosomes, which are intracellular vesicles comprising a magnetic particle. A series of magnetosomes arrange themselves in chains to form a magnetic dipole that enables the cell to orient itself along the Earth’s magnetic field. MamK, an actin-like homolog...
Autores principales: | , , , , , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Public Library of Science
2012
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3346761/ https://www.ncbi.nlm.nih.gov/pubmed/22586444 http://dx.doi.org/10.1371/journal.pone.0034189 |
_version_ | 1782232221948575744 |
---|---|
author | Sonkaria, Sanjiv Fuentes, Gloria Verma, Chandra Narang, Ram Khare, Varsha Fischer, Anna Faivre, Damien |
author_facet | Sonkaria, Sanjiv Fuentes, Gloria Verma, Chandra Narang, Ram Khare, Varsha Fischer, Anna Faivre, Damien |
author_sort | Sonkaria, Sanjiv |
collection | PubMed |
description | Magnetotactic bacteria (MTB) synthesize magnetosomes, which are intracellular vesicles comprising a magnetic particle. A series of magnetosomes arrange themselves in chains to form a magnetic dipole that enables the cell to orient itself along the Earth’s magnetic field. MamK, an actin-like homolog of MreB has been identified as a central component in this organisation. Gene deletion, fluorescence microscopy and in vitro studies have yielded mechanistic differences in the filament assembly of MamK with other bacterial cytoskeletal proteins within the cell. With little or no information on the structural and behavioural characteristics of MamK outside the cell, the mamK gene from Magnetospirillium gryphiswaldense was cloned and expressed to better understand the differences in the cytoskeletal properties with its bacterial homologues MreB and acitin. Despite the low sequence identity shared between MamK and MreB (22%) and actin (18%), the behaviour of MamK monitored by light scattering broadly mirrored that of its bacterial cousin MreB primarily in terms of its pH, salt, divalent metal-ion and temperature dependency. The broad size variability of MamK filaments revealed by light scattering studies was supported by transmission electron microscopy (TEM) imaging. Filament morphology however, indicated that MamK conformed to linearly orientated filaments that appeared to be distinctly dissimilar compared to MreB suggesting functional differences between these homologues. The presence of a nucleotide binding domain common to actin-like proteins was demonstrated by its ability to function both as an ATPase and GTPase. Circular dichroism and structural homology modelling showed that MamK adopts a protein fold that is consistent with the ‘classical’ actin family architecture but with notable structural differences within the smaller domains, the active site region and the overall surface electrostatic potential. |
format | Online Article Text |
id | pubmed-3346761 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2012 |
publisher | Public Library of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-33467612012-05-14 Insight into the Assembly Properties and Functional Organisation of the Magnetotactic Bacterial Actin-like Homolog, MamK Sonkaria, Sanjiv Fuentes, Gloria Verma, Chandra Narang, Ram Khare, Varsha Fischer, Anna Faivre, Damien PLoS One Research Article Magnetotactic bacteria (MTB) synthesize magnetosomes, which are intracellular vesicles comprising a magnetic particle. A series of magnetosomes arrange themselves in chains to form a magnetic dipole that enables the cell to orient itself along the Earth’s magnetic field. MamK, an actin-like homolog of MreB has been identified as a central component in this organisation. Gene deletion, fluorescence microscopy and in vitro studies have yielded mechanistic differences in the filament assembly of MamK with other bacterial cytoskeletal proteins within the cell. With little or no information on the structural and behavioural characteristics of MamK outside the cell, the mamK gene from Magnetospirillium gryphiswaldense was cloned and expressed to better understand the differences in the cytoskeletal properties with its bacterial homologues MreB and acitin. Despite the low sequence identity shared between MamK and MreB (22%) and actin (18%), the behaviour of MamK monitored by light scattering broadly mirrored that of its bacterial cousin MreB primarily in terms of its pH, salt, divalent metal-ion and temperature dependency. The broad size variability of MamK filaments revealed by light scattering studies was supported by transmission electron microscopy (TEM) imaging. Filament morphology however, indicated that MamK conformed to linearly orientated filaments that appeared to be distinctly dissimilar compared to MreB suggesting functional differences between these homologues. The presence of a nucleotide binding domain common to actin-like proteins was demonstrated by its ability to function both as an ATPase and GTPase. Circular dichroism and structural homology modelling showed that MamK adopts a protein fold that is consistent with the ‘classical’ actin family architecture but with notable structural differences within the smaller domains, the active site region and the overall surface electrostatic potential. Public Library of Science 2012-05-07 /pmc/articles/PMC3346761/ /pubmed/22586444 http://dx.doi.org/10.1371/journal.pone.0034189 Text en Sonkaria et al. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited. |
spellingShingle | Research Article Sonkaria, Sanjiv Fuentes, Gloria Verma, Chandra Narang, Ram Khare, Varsha Fischer, Anna Faivre, Damien Insight into the Assembly Properties and Functional Organisation of the Magnetotactic Bacterial Actin-like Homolog, MamK |
title | Insight into the Assembly Properties and Functional Organisation of the Magnetotactic Bacterial Actin-like Homolog, MamK |
title_full | Insight into the Assembly Properties and Functional Organisation of the Magnetotactic Bacterial Actin-like Homolog, MamK |
title_fullStr | Insight into the Assembly Properties and Functional Organisation of the Magnetotactic Bacterial Actin-like Homolog, MamK |
title_full_unstemmed | Insight into the Assembly Properties and Functional Organisation of the Magnetotactic Bacterial Actin-like Homolog, MamK |
title_short | Insight into the Assembly Properties and Functional Organisation of the Magnetotactic Bacterial Actin-like Homolog, MamK |
title_sort | insight into the assembly properties and functional organisation of the magnetotactic bacterial actin-like homolog, mamk |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3346761/ https://www.ncbi.nlm.nih.gov/pubmed/22586444 http://dx.doi.org/10.1371/journal.pone.0034189 |
work_keys_str_mv | AT sonkariasanjiv insightintotheassemblypropertiesandfunctionalorganisationofthemagnetotacticbacterialactinlikehomologmamk AT fuentesgloria insightintotheassemblypropertiesandfunctionalorganisationofthemagnetotacticbacterialactinlikehomologmamk AT vermachandra insightintotheassemblypropertiesandfunctionalorganisationofthemagnetotacticbacterialactinlikehomologmamk AT narangram insightintotheassemblypropertiesandfunctionalorganisationofthemagnetotacticbacterialactinlikehomologmamk AT kharevarsha insightintotheassemblypropertiesandfunctionalorganisationofthemagnetotacticbacterialactinlikehomologmamk AT fischeranna insightintotheassemblypropertiesandfunctionalorganisationofthemagnetotacticbacterialactinlikehomologmamk AT faivredamien insightintotheassemblypropertiesandfunctionalorganisationofthemagnetotacticbacterialactinlikehomologmamk |