Team:Washington/Magnetosomes/Magnet Toolkit

From 2011.igem.org

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(→Construction of the Magnetosome Genome (in parts) in E.coli)
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__NOTOC__
__NOTOC__
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==Magnetosome Toolkit==
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<center><big><big><big><big>'''iGEM Toolkits: Magnetosomes'''</big></big></big></big></center><br><br>
===What are magnetosomes? Where do they come from?===
===What are magnetosomes? Where do they come from?===
 +
[[File:Washington iGEM2011 magnetotatic bacteria picture.jpg|thumb|right|350px|Magnetotactic Bacteria (left) and Magnetosome chains (right)]]
 +
<br> Magnetotactic bacteria are prokaryotic organisms that possess the unique ability to align themselves along a magnetic field. This form of taxis is made possible by the formation of a magnetosome. Magnetosomes are small invaginations of the bacterial inner membrane that contain magnetite particles.
-
[[File:Magnetosome_chain.png‎|thumb|Fig. 1: A Chain of Magnetosomes within ''Magnetospirillum magneticum'' AMB-1]]
+
These particles range in size between 20 and several hundred nanometers and are aligned in one or several chains along the long axis of the bacteria. These particles act together to form a magnetic dipole across the bacteria, allowing it to sense the earth’s magnetic field. Magnetotactic bacteria are microaerophilic; therefore, magnetosomes are thought to help aid the organism in its search for the optimal oxygen level from a search in three dimensional space (in all directions) to a one dimensional space along a single path.
 +
<br><br><br>
 +
<center>Video demonstration of magnetic property of AMB-1 ([http://youtu.be/evrZEe_q4V4 direct link]):</center>
 +
<html><center><iframe width="420" height="315" src="http://www.youtube.com/embed/evrZEe_q4V4" frameborder="0" allowfullscreen></iframe></center></html>
 +
<br> <br>
 +
<i>Narration text from video:</i> Magnetotactic bacteria are named for their ability to respond to and move along magnetic fields.  They were first discovered in 1975 by Richard Blakemore when he noticed bacteria collecting on the north most edge of a water droplet he had placed on a microscope slide.  Magnetotactic bacteria use a chain of vesicle-bound magnetite particles (known as magnetosomes) as a biological compass to orient themselves along the earth's magnetic field lines.  They then swim along these field lines with flagella.  It is thought that this process evolved to allow magnetotactic bacteria to search for certain micro-environments more efficiently.  Magnetotactic bacteria in the northern hemisphere usually swim northward while those found in the southern hemisphere swim southward.  In both cases this would direct the bacterium downward and is thought to allow it to find bottom sediments in an aqueous environment.  As shown here, when a strong magnetic field is applied to the bacteria they can be moved as the magnetite particles within them become polarized and attracted to the magnetic field source.
-
Magnetotactic Bacteria are prokaryotic organisms which possess the unique ability to align themselves along a magnetic field. This form of taxis is made possible by the formation of a magnetosome formation. Magnetosomes are small invaginations of the bacterial cell membrane that contain magnetite particles
+
===A Closer look at Magnetosome Formation ===
-
These particles range in size between 20 and several hundred nanometers and are aligned in one or several chains along the long axis of the bacteria. These particles act together to form a magnetic dipole across the bacteria, allowing it to perceive the earth’s magnetic field. Magnetotactic bacteria are microaerophilic; therefore, the magnetosome is currently thought to help aid the organism in its search for the perfect oxygen level from a three dimensional space (in all directions) to a one dimensional space along a single path.
+
[[File:F6.medium.png|300px|thumb|right|Diagram of stepwise magnetosome construction within AMB-1]]
 +
<br>
 +
The formation of the magnetosome organelle is a highly regulated, step-wise process requiring a cascade of essential genes. The process is generally hypothesized as four stages:
 +
# Membrane invagination
 +
# Acquiring minerals for magnetite formation
 +
# Iron-oxidation and reduction
 +
# Magnetite nucleation and morphology regulation.
 +
<br> Earlier gene products must be present for later gene products to be formed as shown in the diagram on the right[http://www.pnas.org/content/107/12/5593.full.pdf+html]:
-
===A Closer look at Magnetosome Formation ===
+
<br><br><br>
-
The formation of the magnetosome organelle is a highly regulated, step-wise process requiring a cascade of essential genes. The process is generally hypothesized as four stages: i) membrane invagination, ii) acquiring minerals for magnetite formation, iii) iron-oxidation and reduction, iv) magnetite nucleation and morphology regulation. Earlier gene products must be present for later gene products to be formed as shown in the diagram below: [http://www.pnas.org/content/107/12/5593.full.pdf+html]:
+
===What did the UW iGEM team do with Magnetotactic Bacteria?===
-
[[File:F6.medium.png|center|350px|thumb|Fig. 2: Diagram of stepwise magnetosome construction within AMB-1.]]
+
<br>
 +
It is thought that many of the essential genes associated with magnetosome formation are located within a well-conserved region known as the magnetosome island (MAI). The MAI consists of 14 gene clusters labeled R1-R14 (see diagram below).Our team focused on the genes of the mamAB gene cluster (R5), as they were previously shown to be the only cluster essential for magnetosome membrane biogenesis in AMB-1 (diagram show below).[http://www.pnas.org/content/107/12/5593/F1.expansion.html].
-
===What did the UW iGEM team do with Magnetotactic Bacteria?===
+
The goal of our project was to extract all the essential genes from (R5) required for magnetosome formation and express them in ''E. coli''. We are doing this to learn more about magnetosome formation and the magnet synthesis mechanism, because many of the genes' functions are still unknown in the host species. Using the information we have gained, we have organized a '''Magnetosome Toolkit''' containing most of the essential genes for proper magnetosome formation. Ultimately, we would like to continue expanding the magnetosome toolkit to have enough parts to show complete magnetosome formation in ''E.coli''.
-
 
+
-
It is thought that many of the essential genes associated with magnetosome formation are located within a well-conserved region known as the magnetosome island (MAI). The MAI consists of 14 gene clusters labeled R1-R14 (see diagram below).Our team focused on the genes of the mamAB gene cluster (R5)  as they were previously shown to be essential for magnetosome membrane biogenesis in AMB-1 (diagram show below).[http://www.pnas.org/content/107/12/5593/F1.expansion.html].
+
-
 
+
-
The goal of our project was to extract all the essential genes from (R5) required for magnetosome formation and express them in E.coli. This was done in order to understand more about magnetosome formation and the magnet synthesis mechanism because many of the genes' functions are still unknown in the host species. Using the information we have gained, we have organized a '''Magnetosome Toolkit''' containing most of the essential genes for proper magnetosome formation. Ultimately, we would like to continue expanding the magnetosome toolkit to have enough parts to show complete magnetosome formation within E.coli.
+
[[File:MamAB.png|center|500px|thumb|Fig. 3: The mamAB operon (R5) located in the magnetosome island (MAI).]]
[[File:MamAB.png|center|500px|thumb|Fig. 3: The mamAB operon (R5) located in the magnetosome island (MAI).]]
 +
<br>
 +
==='''About the Magnetosome Toolkit'''===
 +
<br>
 +
Using standard synthetic biology protocols and the vectors we created in our Gibson Assembly Toolkit, our team created the '''"Magnetosome Toolkit"''' which contains many of the genes required for magnetosome formation. Providing this toolkit to the Parts Registry will help allow future iGEM teams to manipulate and further understand magnetosome formation to eventually synthesize magnets in multiple organisms.
 +
<br> <br/>
 +
As previously noted, magnetosome formation within the host-organism, ''Magnetospirillium magneticum'', strain AMB-1, is a highly regulated step-wise process. As shown in diagram of stepwise magnetosome construction above, some genes encode proteins that form an invagination of the inner membrane, other genes which help align the magnetosomes into their characteristics chains, and others which regulate the biomineralization of magnetic particles. Our team chose to focus on genes specifically related to magnetosome scaffolding/alignment since they are the essential foundation for magnetosome development. In addition, the creation of a scaffold to which other genes localize is highly applicable to systems in synthetic biology. (for more information, please see our [https://2011.igem.org/Team:Washington/Magnetosomes/Future Future Directions] page)
 +
<br>
-
===About the Magnetosome Toolkit:===
+
The genes we focused on are <i>mamK</i> and <i>mamI</i> since they have known functions related to localization of the magnetosome. Specifically, MamK is a bacterial actin-like cytoskeleton protein required for proper alignment of the magnetosomes in a chain. MamK is also shown to localize the MamI, which when lost inhibits vesicle formation.  
-
 
+
(for other gene functions, please see the iGEM Toolkits parts submitted page)
-
Using standard synthetic biology protocols and the vectors we created in our Gibson Assembly Toolkit, our team was able to create a '''"Magnetosome Toolkit"''' consisting of the most basic parts required for magnetosome formation. Providing this toolkit will help allow future iGem teams to manipulate and further understand magnetosome formation to eventually synthesize magnets in various types of bacteria.
+
<br> <br>
-
 
+
-
 
+
-
 
+
-
=== Toolkit construction and mamAB assembly in E.coli ===
+
-
 
+
-
== Individual Magnetosome (mam) genes==
+
-
 
+
-
Before piecing together the 16 kb genome of the mamAB gene cluster within the magnetosome island (MAI), we extracted out the genes in the following groups:
+
-
 
+
-
{| class="wikitable"
+
-
|-
+
-
! Gene groups
+
-
! Length (bp)
+
-
|-
+
-
| mamHI
+
-
| 1541
+
-
|-
+
-
| mamE
+
-
| 2172
+
-
|-
+
-
| mamJ
+
-
| 1538
+
-
|-
+
-
| mamKL
+
-
| 1336
+
-
|-
+
-
| mamMN
+
-
| 2323
+
-
|-
+
-
| mamO
+
-
| 1914
+
-
|-
+
-
| mamPA
+
-
| 1493
+
-
|-
+
-
| mamQRB
+
-
| 2029
+
-
|- 
+
-
| mamSTU
+
-
| 2030
+
-
|-
+
-
| mamV
+
-
| 1002
+
-
|-
+
-
|}.
+
-
 
+
-
[[File:Washington Methode image.jpg|right|500px]]
+
-
 
+
-
Using standard protocols and our high-copy pGA vectors, these genes were extracted from the host genome and characterized to confirm their accuracy.
+
-
 
+
-
As previously noted, magnetosome formation within the host-organism, ''Magnetospirillium magneticum'', strain AMB-1, is a highly regulated step-wise process. As shown in Fig. 2, some genes encode for an invagination in the inner membrane, other genes which help align the magnetosomes into their characteristics chains, and others which regulate the biomineralization of magnetic particles. Our team chose to focus on genes specifically related to magnetosome scaffolding/alignment since they are the essential foundation for magnetosome development. In addition, the creation of a scaffold to which other genes localize is highly applicable to systems in synthetic biology. (for more information, please see our Future Directions page)
+
-
 
+
-
Our genes of interest were mamK and mamI as they have functions related to localization of the magnetosome. Specifically, mamK is a bacterial actin-like cytoskeleton protein required for proper alignment of the magnetosomes in a chain. mamK is also shown to localize the mamI, which is loss inhibits membrane formation.  
+
-
(for other gene functions, see the table below):
+
-
 
+
-
{| class="wikitable"
+
-
|-
+
-
! Gene
+
-
! AMB Number
+
-
! Cluster Membership
+
-
! Member of 28 genes list? (specific*/related**)
+
-
! Function Summary (Vesicle chain formation, and/or biomineralization)
+
-
! Gene Function
+
-
|-
+
-
| mamH
+
-
| amb0961
+
-
| mamAB
+
-
| Related
+
-
|
+
-
|
+
-
|-
+
-
| mamI
+
-
| amb0962
+
-
| mamAB
+
-
| Specific
+
-
| Vesicle, (Chain Formation?)
+
-
| >berkeley 2010: Loss causes no membrane formation, is localized onto chains
+
-
|-
+
-
| mamE
+
-
| amb0963
+
-
| mamAB; mam Islet
+
-
| Related
+
-
|
+
-
| >Membrane-bound serine protease required for magnetite formation; might control the localization of other magnetosome proteins
+
-
|-
+
-
| mamJ
+
-
| amb0964
+
-
| mamAB; mam Islet
+
-
| Specific
+
-
| Chain Formation
+
-
| >Proper magnetosome chain organization/assembly
+
-
|-
+
-
| mamK
+
-
| amb0965
+
-
| mamAB; mam Islet
+
-
| Related
+
-
| Chain Formation
+
-
| >required for proper magnetosome chain organization; *bacterial actin-like cytoskeleton protein required for proper alignment of the magnetosomes in a chain, shown to localize the mamI
+
-
|-
+
-
| mamL
+
-
| amb0966
+
-
| mamAB; mam Islet
+
-
| Specific
+
-
| Vesicle, biomineralization
+
-
| >berkely 2010: Crucial to mangneosome membrane creation, shown to be spread across the cell membrane and sometimes forms lines
+
-
|-
+
-
| mamM
+
-
| amb0967
+
-
| mamAB
+
-
| Related
+
-
|
+
-
| >biomineralization, involved in iron transport, magnetite nucleation, or establishement of the proper chemical enviornment for magnetite synthesis in the magnetosome
+
-
|-
+
-
| mamN
+
-
| amb0968
+
-
| mamAB
+
-
| Related
+
-
|
+
-
| >biomineralization, involved in iron transport, magnetite nucleation, or establishement of the proper chemical enviornment for magnetite synthesis in the magnetosome
+
-
|-
+
-
| mamO
+
-
| amb0969
+
-
| mamAB
+
-
| Related
+
-
|
+
-
| >biomineralization, involved in iron transport, magnetite nucleation, or establishement of the proper chemical enviornment for magnetite synthesis in the magnetosome
+
-
|- 
+
-
| mamP
+
-
| amb0970
+
-
| mamAB
+
-
| Related
+
-
| Biomineralization
+
-
| >berkeley 2010: loss causes weak magnetic response, with large but fewer crystals
+
-
|-
+
-
| mamA
+
-
| amb0971
+
-
| mamAB
+
-
| Related
+
-
|
+
-
| >Required for magnetosome activation; activation of vessicles
+
-
|-
+
-
| mamQ
+
-
| amb0972
+
-
| mamAB; mam Islet
+
-
| Related
+
-
|
+
-
| >ORF; formation/maintenance of magnetosome membranes
+
-
|-
+
-
| mamR
+
-
| amb0973
+
-
| mamAB
+
-
| Specific
+
-
| Chain formation, Biomineralization
+
-
| >ORF; plays a role in controlling both particle number and size of magnetite cyrstals
+
-
|-
+
-
| mamB
+
-
| amb0974
+
-
| mamAB
+
-
| Related
+
-
| Vesicle, Biomineralization
+
-
| >indirect role in magnetosome membrane invagination and biomineralization; magnetosome compartment formation
+
-
|-
+
-
| mamS
+
-
| amb0975
+
-
| mamAB
+
-
| Specific
+
-
|
+
-
|
+
-
|-
+
-
| mamT
+
-
| amb0976
+
-
| mamAB
+
-
| Specific
+
-
| Biomineralization
+
-
| >magnetite crystal growth; participates in different steps during magnetite synthesis
+
-
|-
+
-
| mamU
+
-
| amb0977
+
-
| mamAB
+
-
| Related
+
-
|
+
-
|
+
-
|-
+
-
| mamV
+
-
| amb0978
+
-
| mamAB
+
-
| N/A
+
-
|
+
-
|
+
-
|-
+
-
|}
+
-
 
+
-
== Magnetosome gene-protein Fusions==
+
-
 
+
-
Using our two genes of interest, we created C-terminal sfGFP fusions so we could track the localization of each gene separately within ''E.coli.''
+
 +
==='''Toolkit Contruction'''===
 +
[[File:Washington Methode image.jpg|700px|center]]
-
[[File:Igem2011_mamK_and_I.png|700px|center]]
+
<br/>Please see our [https://2011.igem.org/Team:Washington/Magnetosomes/Magnet_Results Result Summary] page for to see how far we were able to get this summer!
-
The results we obtained with our sfGFP fusions inside ''E.coli'' were comparable to those done through other studies in the host organism ''Magnetospirillum magneticum''. In the image of  mamK, a filament is seen running through the length of many bacteria. For mamI, the gene product is seen to fluoresce around the cell membrane of the bacteria but mostly concentrated at the ends. Similarly, the graph shows that as the arrow cross the cell membrane, the fluorescent peaks are at a maximum, and through the center of the cell, the level of fluorescence decreases.
+
<br/>
-
==Construction of the R5 region of the Magnetosome Island in ''E.coli''==
+
=References:=
-
After identifying that the construction of the scaffold  had worked, we proceeded to work on the final assembly in three parts: mamHIEJLK, mamMNOPA, and mamQRBSTUV. The first, and the third part of the assembly are shown below. They have been sequence confirmed...
 
-
------>Pictures of mamHIEJLK and QRBSTUV<-------
+
# Matsunaga, T., Okamura, Y., Fukuda, Y., Wahyudi, A.T., Murase, Y., Takeyama, H. (2005). Complete genome sequence of the facultative anaerobic Magnetotactic bacterium Magnetospirillum sp. strain AMB-1. ''DNA research''; 12: 157-166. Doi:10.1093/dnares/dsi002.
 +
# Murat, D., Quinlan, A., Vali, H., Komeili, A. (2010). Comprehensive genetic dissection of the magnetosome gene island reveals the step-wise assembly of a prokaryotic organelle. ''PNAS''; 107 (12): 5593-5598. Doi:10.1073/pnas.0914439107.
 +
# Murat, D., Quinlan, A., Vali, H., Komeili, A. (2010). Supporting Information. ''PNAS''; 107 (12): 5593-5598. Doi:10.1073/pnas.0914439107.
 +
# Quinlan, A., Murat, D., Vali, H., Komeili, A. (2011).The HtrA/DegP family protease MamE is a bifunctional protein with roles in magnetosome protein localization and magnetite biomineralization. ''Molecular Microbiology''; 80 (4): 855-1131. Doi:10.1111/j.1365-2958.2011.07631.x.
 +
# Richter, M., Kube, M., Bazylinski, D.A., Lombardot, T.,Glockner, F.O., Reinhardt, R., Shuler, D. (2007). Comparative genome analysis of four Magnetotactic bacteria reveals a complex set of group-specific genes implicated in magnetosome biomineralization and function. ''Journal of Bacteriology''; 189(13): 4899-4910. Doi:10.1128/JB.00119-07.
 +
# Rioux, J.B., Philippe, N., Pereia, S., Pignol, D., Wu, L.F., Ginet, N. (2010). A second actin-like mamK protein in Magnetospirillum magneticum AMB-1 encoded outside the genomic magnetosome island. ''PLoS ONE''; 5(2): e9151. Doi:10.1371/journal.pone.0009151.

Latest revision as of 18:45, 27 October 2011


iGEM Toolkits: Magnetosomes


What are magnetosomes? Where do they come from?

Magnetotactic Bacteria (left) and Magnetosome chains (right)


Magnetotactic bacteria are prokaryotic organisms that possess the unique ability to align themselves along a magnetic field. This form of taxis is made possible by the formation of a magnetosome. Magnetosomes are small invaginations of the bacterial inner membrane that contain magnetite particles.

These particles range in size between 20 and several hundred nanometers and are aligned in one or several chains along the long axis of the bacteria. These particles act together to form a magnetic dipole across the bacteria, allowing it to sense the earth’s magnetic field. Magnetotactic bacteria are microaerophilic; therefore, magnetosomes are thought to help aid the organism in its search for the optimal oxygen level from a search in three dimensional space (in all directions) to a one dimensional space along a single path.


Video demonstration of magnetic property of AMB-1 ([http://youtu.be/evrZEe_q4V4 direct link]):



Narration text from video: Magnetotactic bacteria are named for their ability to respond to and move along magnetic fields. They were first discovered in 1975 by Richard Blakemore when he noticed bacteria collecting on the north most edge of a water droplet he had placed on a microscope slide. Magnetotactic bacteria use a chain of vesicle-bound magnetite particles (known as magnetosomes) as a biological compass to orient themselves along the earth's magnetic field lines. They then swim along these field lines with flagella. It is thought that this process evolved to allow magnetotactic bacteria to search for certain micro-environments more efficiently. Magnetotactic bacteria in the northern hemisphere usually swim northward while those found in the southern hemisphere swim southward. In both cases this would direct the bacterium downward and is thought to allow it to find bottom sediments in an aqueous environment. As shown here, when a strong magnetic field is applied to the bacteria they can be moved as the magnetite particles within them become polarized and attracted to the magnetic field source.

A Closer look at Magnetosome Formation

Diagram of stepwise magnetosome construction within AMB-1


The formation of the magnetosome organelle is a highly regulated, step-wise process requiring a cascade of essential genes. The process is generally hypothesized as four stages:

  1. Membrane invagination
  2. Acquiring minerals for magnetite formation
  3. Iron-oxidation and reduction
  4. Magnetite nucleation and morphology regulation.


Earlier gene products must be present for later gene products to be formed as shown in the diagram on the right[http://www.pnas.org/content/107/12/5593.full.pdf+html]:




What did the UW iGEM team do with Magnetotactic Bacteria?


It is thought that many of the essential genes associated with magnetosome formation are located within a well-conserved region known as the magnetosome island (MAI). The MAI consists of 14 gene clusters labeled R1-R14 (see diagram below).Our team focused on the genes of the mamAB gene cluster (R5), as they were previously shown to be the only cluster essential for magnetosome membrane biogenesis in AMB-1 (diagram show below).[http://www.pnas.org/content/107/12/5593/F1.expansion.html].

The goal of our project was to extract all the essential genes from (R5) required for magnetosome formation and express them in E. coli. We are doing this to learn more about magnetosome formation and the magnet synthesis mechanism, because many of the genes' functions are still unknown in the host species. Using the information we have gained, we have organized a Magnetosome Toolkit containing most of the essential genes for proper magnetosome formation. Ultimately, we would like to continue expanding the magnetosome toolkit to have enough parts to show complete magnetosome formation in E.coli.

Fig. 3: The mamAB operon (R5) located in the magnetosome island (MAI).


About the Magnetosome Toolkit


Using standard synthetic biology protocols and the vectors we created in our Gibson Assembly Toolkit, our team created the "Magnetosome Toolkit" which contains many of the genes required for magnetosome formation. Providing this toolkit to the Parts Registry will help allow future iGEM teams to manipulate and further understand magnetosome formation to eventually synthesize magnets in multiple organisms.

As previously noted, magnetosome formation within the host-organism, Magnetospirillium magneticum, strain AMB-1, is a highly regulated step-wise process. As shown in diagram of stepwise magnetosome construction above, some genes encode proteins that form an invagination of the inner membrane, other genes which help align the magnetosomes into their characteristics chains, and others which regulate the biomineralization of magnetic particles. Our team chose to focus on genes specifically related to magnetosome scaffolding/alignment since they are the essential foundation for magnetosome development. In addition, the creation of a scaffold to which other genes localize is highly applicable to systems in synthetic biology. (for more information, please see our Future Directions page)

The genes we focused on are mamK and mamI since they have known functions related to localization of the magnetosome. Specifically, MamK is a bacterial actin-like cytoskeleton protein required for proper alignment of the magnetosomes in a chain. MamK is also shown to localize the MamI, which when lost inhibits vesicle formation. (for other gene functions, please see the iGEM Toolkits parts submitted page)

Toolkit Contruction

Washington Methode image.jpg


Please see our Result Summary page for to see how far we were able to get this summer!


References:

  1. Matsunaga, T., Okamura, Y., Fukuda, Y., Wahyudi, A.T., Murase, Y., Takeyama, H. (2005). Complete genome sequence of the facultative anaerobic Magnetotactic bacterium Magnetospirillum sp. strain AMB-1. DNA research; 12: 157-166. Doi:10.1093/dnares/dsi002.
  2. Murat, D., Quinlan, A., Vali, H., Komeili, A. (2010). Comprehensive genetic dissection of the magnetosome gene island reveals the step-wise assembly of a prokaryotic organelle. PNAS; 107 (12): 5593-5598. Doi:10.1073/pnas.0914439107.
  3. Murat, D., Quinlan, A., Vali, H., Komeili, A. (2010). Supporting Information. PNAS; 107 (12): 5593-5598. Doi:10.1073/pnas.0914439107.
  4. Quinlan, A., Murat, D., Vali, H., Komeili, A. (2011).The HtrA/DegP family protease MamE is a bifunctional protein with roles in magnetosome protein localization and magnetite biomineralization. Molecular Microbiology; 80 (4): 855-1131. Doi:10.1111/j.1365-2958.2011.07631.x.
  5. Richter, M., Kube, M., Bazylinski, D.A., Lombardot, T.,Glockner, F.O., Reinhardt, R., Shuler, D. (2007). Comparative genome analysis of four Magnetotactic bacteria reveals a complex set of group-specific genes implicated in magnetosome biomineralization and function. Journal of Bacteriology; 189(13): 4899-4910. Doi:10.1128/JB.00119-07.
  6. Rioux, J.B., Philippe, N., Pereia, S., Pignol, D., Wu, L.F., Ginet, N. (2010). A second actin-like mamK protein in Magnetospirillum magneticum AMB-1 encoded outside the genomic magnetosome island. PLoS ONE; 5(2): e9151. Doi:10.1371/journal.pone.0009151.
Retrieved from "http://2011.igem.org/Team:Washington/Magnetosomes/Magnet_Toolkit"