Sandbox 81: Difference between revisions
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{{Professor Oberholser Student Reservation until September 28, 2009 for Biochemistry 410 at Messiah College.}} | {{Professor Oberholser Student Reservation until September 28, 2009 for Biochemistry 410 at Messiah College.}} | ||
== '''Alpha Lactalbumin''' == | == '''Alpha Lactalbumin''' == | ||
α-lactalbumin is a | α-lactalbumin is a small acidic protein present in all kinds of milk studied thus far. <ref name="vilotte"> Vilotte JL. Alpha-lactalbumin: Gene Structure and Expression. <http://mammary.nih.gov/Reviews/gene_expression/Vilotte001/index.html>. </ref> | ||
α- lactalbumin contributes to cell lytic activity, cell growth inhibition, and apoptosis but most importantly, it interacts with UDP-galactosyltransferase <ref name="vilotte"> </ref> to form lactose synthetase via the following reaction: | α- lactalbumin contributes to cell lytic activity, cell growth inhibition, and apoptosis but most importantly, it interacts with UDP-galactosyltransferase <ref name="vilotte"> </ref> to form lactose synthetase via the following reaction: | ||
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which takes place in the Golgi lumen and requires Mn2+ ions <ref name="structure"> Permyakov EA, Berliner LJ. α-Lactalbumin: structure and function. 2000. FEBS Letters. 473(3):269-274. </ref>. | which takes place in the Golgi lumen and requires Mn2+ ions <ref name="structure"> Permyakov EA, Berliner LJ. α-Lactalbumin: structure and function. 2000. FEBS Letters. 473(3):269-274. </ref>. | ||
{{STRUCTURE_1a4v | PDB=1a4v | SCENE= }} | {{STRUCTURE_1a4v | PDB=1a4v | SCENE= }} | ||
== Structure == | == Structure == | ||
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The <scene name='Sandbox_81/Secondary_structure/1'>secondary structure</scene> has nine alpha helices shown as pink rockets, and two beta sheets shown as yellow planks.<ref name="PDB"> </ref> The four disulfide bonds are shown by the yellow strings. It also has three strands, and 2 beta hairpins, and 11 beta turns. | The <scene name='Sandbox_81/Secondary_structure/1'>secondary structure</scene> has nine alpha helices shown as pink rockets, and two beta sheets shown as yellow planks.<ref name="PDB"> </ref> The four disulfide bonds are shown by the yellow strings. It also has three strands, and 2 beta hairpins, and 11 beta turns. | ||
The <scene name='Sandbox_81/Side_chains/1'>side | The <scene name='Sandbox_81/Side_chains/1'>side chains</scene> are shown here with nonpolar side chains in gray, polar side chains in purple, and associated water molecules in red. The hydrophobic side chains congregate in the center of the protein with the polar side chains on the periphery. The water molecules are associated with the polar side chains. | ||
<scene name='Sandbox_81/Residues/1'> | Here are shown the <scene name='Sandbox_81/Residues/1'>polar uncharged residues</scene> with the cations in blue, the anions in red, hydrophobic residues in gray, polar uncharged residues in light purple, and the backbone residues in dark purple. | ||
In the beta-rich domain there are two calcium binding sites, shown here are the <scene name='Sandbox_81/Ligands/2'>calcium ligands</scene> with their amino acid contacts (water molecules are shown in pink and oxygen molecules are shown in red). The first site, the primary site is made of three asparagine side chains and two carbonyls <ref name="PDB"> </ref>, and has a pentagonal bypyramidal coordination with active sites: LYS A 79 ASP A 82 ASP A 84 ASP A 87 ASP A 88. The second site has a tetrahedral coordination with active sites: THR A 38 GLN A 39 LEU A 81 ASP A 83 <ref name="PDB"> </ref>. | In the beta-rich domain there are two calcium binding sites, shown here are the <scene name='Sandbox_81/Ligands/2'>calcium ligands</scene> with their amino acid contacts (water molecules are shown in pink and oxygen molecules are shown in red). The first site, the primary site is made of three asparagine side chains and two carbonyls <ref name="PDB"> </ref>, and has a pentagonal bypyramidal coordination with active sites: LYS A 79 ASP A 82 ASP A 84 ASP A 87 ASP A 88. The second site has a tetrahedral coordination with active sites: THR A 38 GLN A 39 LEU A 81 ASP A 83 <ref name="PDB"> </ref>. | ||
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Many studies have found that infants who are formula- fed have different growth and amino acid patterns from breast-fed infants from the lack of alpha-lactalbumin. The addition of bovine alpha-lactalbumin to formula makes the growth and plasma amino acid patterns of formula-fed infants more similar to those of breast-fed infants, and improves their growth.<ref name="infant"> Sandström O, Lönnderdal B, Graverholt G, Hernell O. 2008. Effects of alpha-lactalbumin-enriched formula containing different concentrations of glycomacropeptide on infant nutrition. Am J Clin Nutr. 87(4): 921-928.</ref> | Many studies have found that infants who are formula- fed have different growth and amino acid patterns from breast-fed infants from the lack of alpha-lactalbumin. The addition of bovine alpha-lactalbumin to formula makes the growth and plasma amino acid patterns of formula-fed infants more similar to those of breast-fed infants, and improves their growth.<ref name="infant"> Sandström O, Lönnderdal B, Graverholt G, Hernell O. 2008. Effects of alpha-lactalbumin-enriched formula containing different concentrations of glycomacropeptide on infant nutrition. Am J Clin Nutr. 87(4): 921-928.</ref> | ||
HAMLET (human alpha-lactalbumin made lethal to tumor cells) is the topic of much recent study. Alpha-lactalbumin is converted into a folding variant with altered biological function which can induce apoptosis in tumor and premature cells, healthy cells are resistant to this. For HAMLET to form partial unfolding needs to occur, as well as the presence of C18:1, a fatty acid. The studies have shown that HAMLET may help lower cancer in breast-fed infants by killing the tumor cells in their stomachs because the low pH releases Ca21 from the binding site and activates lipases that hydrolyze free fatty acids from milk triglycerides.<ref name="apoptosis"> Svensson M, Hakansson A, Mossberg AK, Linse S, Svanborg C. 2000. Conversion of α-lactalbumin to a protein inducing apoptosis. PNAS. 97(8): 4221-4226.</ref> | HAMLET (human alpha-lactalbumin made lethal to tumor cells) is the topic of much recent study. Alpha-lactalbumin is converted into a folding variant with altered biological function which can induce apoptosis in tumor and premature cells, healthy cells are resistant to this. For HAMLET to form partial unfolding needs to occur, as well as the presence of C18:1, a fatty acid. The studies have shown that HAMLET may help lower cancer in breast-fed infants by killing the tumor cells in their stomachs because the low pH releases Ca21 from the binding site and activates lipases that hydrolyze free fatty acids from milk triglycerides.<ref name="apoptosis"> Svensson M, Hakansson A, Mossberg AK, Linse S, Svanborg C. 2000. Conversion of α-lactalbumin to a protein inducing apoptosis. PNAS. 97(8): 4221-4226.</ref> | ||
==References== | ==References== | ||
<references/> | <references/> | ||