Alpha crystallin: Difference between revisions

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== Function ==

Alpha crystallin is known to be one of the primary structural proteins of the eye's lens, specifically crystallin types alpha (α), beta (β), and gamma (γ). While all types have essential roles in the eye, alpha-crystallin and its subunits make up 40% of the lens's protein composition <ref> DOI: 10.1016/j.preteyeres.2006.10.003 </ref>. These crystallin proteins create stability in the lens and have the ability to impact an individual's vision because they provide lens transparency. In order to retain their eye's transparency in the absence of protein turnover, or the replacing and reproduction of proteins within a cell as the proteins become broken down, the protein must retain some form of longevity. Its longevity is generally assumed to be correlated with the long-term retention of its <scene name='88/881544/Native_structure/1'>native structure</scene>. Its ability to maintain the structure for a prolonged period of time is related to the N-terminal residue as this terminal is correlated with protein life. Even though the N-terminal does impact protein longevity, it does not determine a protein's half-life completely. In alpha-crystallin, the N-terminus contains approximately 60 residues, some of which include isoleucine and alanine <ref> DOI: 10.1016/j.pbiomolbio.2003.11.012 </ref>.

'''Alpha crystallin''' is known to be one of the primary structural proteins of the eye's lens, specifically crystallin types alpha (α), beta (β), and gamma (γ). While all types have essential roles in the eye, alpha-crystallin and its subunits make up 40% of the lens's protein composition <ref> DOI: 10.1016/j.preteyeres.2006.10.003 </ref>. These crystallin proteins create stability in the lens and have the ability to impact an individual's vision because they provide lens transparency. In order to retain their eye's transparency in the absence of protein turnover, or the replacing and reproduction of proteins within a cell as the proteins become broken down, the protein must retain some form of longevity. Its longevity is generally assumed to be correlated with the long-term retention of its <scene name='88/881544/Native_structure/1'>native structure</scene>. Its ability to maintain the structure for a prolonged period of time is related to the N-terminal residue as this terminal is correlated with protein life. Even though the N-terminal does impact protein longevity, it does not determine a protein's half-life completely. In alpha-crystallin, the N-terminus contains approximately 60 residues, some of which include isoleucine and alanine <ref> DOI: 10.1016/j.pbiomolbio.2003.11.012 </ref>.

This means that the half-life of an alpha-crystallin protein, based on the N-terminal residues' contents, may be about 20 hours <ref> DOI: 10.1126/science.3018930 </ref>. Its native structure can remain intact due to the efficient capture and refolding process of non-native proteins by the chaperones and the thermodynamic stability that the proteins have. Alpha-crystallins also provide vision clarity by regulating a proper refractive index within the eye. The lens contains a very high concentration of lens crystallins, primarily alpha-crystallin, and they remain densely packed within the space. This allows the lens to maintain a consistent refractive index over various distances, regardless of the light wavelength's location. They also have a particular arrangement of epithelial cells and fiber cells that lack organelles in their nucleases to reduce the blockage of light transmission to the eye <ref> DOI: 10.1016/j.pbiomolbio.2003.11.012 </ref>.

Along with the contents and structure of the lens itself, the alpha-crystallin maintains the eye's clarity by acting as chaperone-like proteins in order to prevent aberrant, or standard deviating, protein interactions. The chaperone capabilities of these proteins also allow the prevention of non-native proteins becoming insoluble under stressful conditions like chemical reductions, oxidations, or elevation of temperatures. The combined abilities of the chaperone-like alpha-crystallin means that they can aid in the prevention of the formation of large, dense, light scattering masses. For example, one of the effects of old age is cataract formation, and alpha-crystallin is the known culprit for this development. As alpha-crystallin is depleted within the eye, its defensive efforts go with it, which allows these masses to take form. The alpha-crystallin within the eye is the primary protectant against the age-induced deterioration of the lens. It allows the effects of aging to be reduced for significant periods of time.

Alpha crystallin: Difference between revisions

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-<Structure load='3L1E' size='350' frame='true' align='right' caption='Insert caption here' scene='Insert optional scene name here' />
+<Structure load='3L1E' size='350' frame='true' align='right' caption='Bovine alpha-cystallin A chain residues 59-163 complex with Zn+2 (grey) (PDB code [[3l1e]])' scene='Insert optional scene name here' />
 == Function ==
-Alpha crystallin is known to be one of the primary structural proteins of the eye's lens, specifically crystallin types alpha (α), beta (β), and gamma (γ). While all types have essential roles in the eye, alpha-crystallin and its subunits make up 40% of the lens's protein composition <ref> DOI: 10.1016/j.preteyeres.2006.10.003 </ref>. These crystallin proteins create stability in the lens and have the ability to impact an individual's vision because they provide lens transparency. In order to retain their eye's transparency in the absence of protein turnover, or the replacing and reproduction of proteins within a cell as the proteins become broken down, the protein must retain some form of longevity. Its longevity is generally assumed to be correlated with the long-term retention of its <scene name='88/881544/Native_structure/1'>native structure</scene>. Its ability to maintain the structure for a prolonged period of time is related to the N-terminal residue as this terminal is correlated with protein life. Even though the N-terminal does impact protein longevity, it does not determine a protein's half-life completely. In alpha-crystallin, the N-terminus contains approximately 60 residues, some of which include isoleucine and alanine <ref> DOI: 10.1016/j.pbiomolbio.2003.11.012 </ref>.
+'''Alpha crystallin''' is known to be one of the primary structural proteins of the eye's lens, specifically crystallin types alpha (α), beta (β), and gamma (γ). While all types have essential roles in the eye, alpha-crystallin and its subunits make up 40% of the lens's protein composition <ref> DOI: 10.1016/j.preteyeres.2006.10.003 </ref>. These crystallin proteins create stability in the lens and have the ability to impact an individual's vision because they provide lens transparency. In order to retain their eye's transparency in the absence of protein turnover, or the replacing and reproduction of proteins within a cell as the proteins become broken down, the protein must retain some form of longevity. Its longevity is generally assumed to be correlated with the long-term retention of its <scene name='88/881544/Native_structure/1'>native structure</scene>. Its ability to maintain the structure for a prolonged period of time is related to the N-terminal residue as this terminal is correlated with protein life. Even though the N-terminal does impact protein longevity, it does not determine a protein's half-life completely. In alpha-crystallin, the N-terminus contains approximately 60 residues, some of which include isoleucine and alanine <ref> DOI: 10.1016/j.pbiomolbio.2003.11.012 </ref>.
 This means that the half-life of an alpha-crystallin protein, based on the N-terminal residues' contents, may be about 20 hours <ref> DOI: 10.1126/science.3018930 </ref>. Its native structure can remain intact due to the efficient capture and refolding process of non-native proteins by the chaperones and the thermodynamic stability that the proteins have. Alpha-crystallins also provide vision clarity by regulating a proper refractive index within the eye. The lens contains a very high concentration of lens crystallins, primarily alpha-crystallin, and they remain densely packed within the space. This allows the lens to maintain a consistent refractive index over various distances, regardless of the light wavelength's location. They also have a particular arrangement of epithelial cells and fiber cells that lack organelles in their nucleases to reduce the blockage of light transmission to the eye <ref> DOI: 10.1016/j.pbiomolbio.2003.11.012 </ref>.
 Along with the contents and structure of the lens itself, the alpha-crystallin maintains the eye's clarity by acting as chaperone-like proteins in order to prevent aberrant, or standard deviating, protein interactions. The chaperone capabilities of these proteins also allow the prevention of non-native proteins becoming insoluble under stressful conditions like chemical reductions, oxidations, or elevation of temperatures. The combined abilities of the chaperone-like alpha-crystallin means that they can aid in the prevention of the formation of large, dense, light scattering masses. For example, one of the effects of old age is cataract formation, and alpha-crystallin is the known culprit for this development. As alpha-crystallin is depleted within the eye, its defensive efforts go with it, which allows these masses to take form. The alpha-crystallin within the eye is the primary protectant against the age-induced deterioration of the lens. It allows the effects of aging to be reduced for significant periods of time.