Difference between revisions of "Team:Queens Canada/Background"
Line 59: | Line 59: | ||
<p>Have you ever wondered how fish and other organisms can survive in sub-zero Arctic Oceans without freezing (Figure 1)? Or why some plants can recover from a frost more easily than others? Some organisms use glycerol or other solutes to tolerate the below-freezing temperatures of extreme environments. However, a large number of diverse species have been found to use a special class of proteins termed antifreeze proteins that inhibit ice growth enabling survival in sub-zero climates.</p> | <p>Have you ever wondered how fish and other organisms can survive in sub-zero Arctic Oceans without freezing (Figure 1)? Or why some plants can recover from a frost more easily than others? Some organisms use glycerol or other solutes to tolerate the below-freezing temperatures of extreme environments. However, a large number of diverse species have been found to use a special class of proteins termed antifreeze proteins that inhibit ice growth enabling survival in sub-zero climates.</p> | ||
<figure style="float: left; width: 400px;"> | <figure style="float: left; width: 400px;"> | ||
− | <img src=" | + | <img src="https://static.igem.org/mediawiki/2015/0/0b/Qqq_QGEM_oceanpout.jpg" style="width: 400px;"/> |
<figcaption>Figure 1. <strong>Image of an ocean pout found in the Northwest Atlantic Ocean <sup>1</sup>.</strong>Ocean pout harbour the Type III Antifreeze Protein in their blood which enables them to survive in cold water.</figcaption> | <figcaption>Figure 1. <strong>Image of an ocean pout found in the Northwest Atlantic Ocean <sup>1</sup>.</strong>Ocean pout harbour the Type III Antifreeze Protein in their blood which enables them to survive in cold water.</figcaption> | ||
</figure> | </figure> | ||
Line 65: | Line 65: | ||
<p>Antifreeze proteins, or AFPs, are naturally occurring, highly diverse proteins with the unique ability to bind to an ice surface. There is great diversity in the structure of AFPs, a consequence of AFPs evolving independently in multiple different species and geographic locations. Despite this vast diversity of structures a common feature of most AFPs is the ability of one face of the protein, termed the ice-binding surface (IBS), to non-covalently bind to ice and inhibit ice growth. The IBS composition and the mechanism of ice inhibition varies between AFPs, however the IBS is generally comprised of small, hydrophobic amino acids that order water molecules in an ice-like array on their ice-binding surface. This array of ordered-waters then hydrogen binds to the ice crystal, anchoring the AFP to the ice surface and inhibiting expansion of the ice (Figure 2).</p> | <p>Antifreeze proteins, or AFPs, are naturally occurring, highly diverse proteins with the unique ability to bind to an ice surface. There is great diversity in the structure of AFPs, a consequence of AFPs evolving independently in multiple different species and geographic locations. Despite this vast diversity of structures a common feature of most AFPs is the ability of one face of the protein, termed the ice-binding surface (IBS), to non-covalently bind to ice and inhibit ice growth. The IBS composition and the mechanism of ice inhibition varies between AFPs, however the IBS is generally comprised of small, hydrophobic amino acids that order water molecules in an ice-like array on their ice-binding surface. This array of ordered-waters then hydrogen binds to the ice crystal, anchoring the AFP to the ice surface and inhibiting expansion of the ice (Figure 2).</p> | ||
<figure> | <figure> | ||
− | <img src=" | + | <img src="https://static.igem.org/mediawiki/2015/9/9e/Qqq_QGEM_icebinding.png" /> |
<figcaption>Figure 2. <strong>Diagram describing the possible mechanisms of AFP ice binding.</strong> The first column <strong>A,</strong> shows the Hydrogen Bonding Hypothesis: threonines at the IBS hydrogen-bond with the upper ice surface and move deeper into the ice. <strong>B</strong> describes the Hydrophobic effect in AFP binding, where methyl groups displace ice-like waters on the ice surface. <strong> C </strong> is the Anchored Clathrate Hypothesis. Figure taken from Davies (2014), Figure 6<sup>2</sup>.</figcaption> | <figcaption>Figure 2. <strong>Diagram describing the possible mechanisms of AFP ice binding.</strong> The first column <strong>A,</strong> shows the Hydrogen Bonding Hypothesis: threonines at the IBS hydrogen-bond with the upper ice surface and move deeper into the ice. <strong>B</strong> describes the Hydrophobic effect in AFP binding, where methyl groups displace ice-like waters on the ice surface. <strong> C </strong> is the Anchored Clathrate Hypothesis. Figure taken from Davies (2014), Figure 6<sup>2</sup>.</figcaption> | ||
</figure> | </figure> | ||
Line 83: | Line 83: | ||
<p align="center"><em>The soul mate story of heterodimer coils.</em></p> | <p align="center"><em>The soul mate story of heterodimer coils.</em></p> | ||
<h2>Coiled-Coil Motifs</h2> | <h2>Coiled-Coil Motifs</h2> | ||
− | <img src=" | + | <img src="https://static.igem.org/mediawiki/2015/1/1a/QGEM_coiledcoil_infographic.png" style="width: 400px; height: auto; float: right; padding: 20px;" /> |
<p>Coiled-coils are a naturally occurring phenomenon. Consisting of multiple alpha-helices, these protein structures are identified as left-handed helices that interact non-covalently. First identified in 1972 by Sodex et al. as a series of hydrophobic repeats within tropomyosin<sup>1</sup>. Similar patterns were also located in fibrous proteins<sup>2</sup> and intermediate filaments<sup>3</sup>. </p> | <p>Coiled-coils are a naturally occurring phenomenon. Consisting of multiple alpha-helices, these protein structures are identified as left-handed helices that interact non-covalently. First identified in 1972 by Sodex et al. as a series of hydrophobic repeats within tropomyosin<sup>1</sup>. Similar patterns were also located in fibrous proteins<sup>2</sup> and intermediate filaments<sup>3</sup>. </p> | ||
<p>Interactions can be engineered to introduce highly specific connections between helical sequences. While many naturally occurring coiled-coils allow non-specific interactions between coils, engineered constructs improve the affinity and specificity of these interactions, creating motifs with strengths nearing that of covalent contacts. </p> | <p>Interactions can be engineered to introduce highly specific connections between helical sequences. While many naturally occurring coiled-coils allow non-specific interactions between coils, engineered constructs improve the affinity and specificity of these interactions, creating motifs with strengths nearing that of covalent contacts. </p> |
Revision as of 14:48, 5 September 2015