Sandbox Reserved 779: Difference between revisions

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The structures of the trigonal crystal form of bovine beta-lactoglobulin variant A at pH 6.2, 7.1, and 8.2 have been determined by X-ray diffraction methods at a resolution of 2.56, 2. 24, and 2.49 A, respectively. The glutamate side chain of residue 89 is buried at pH 6.2 and becomes exposed at pH 7.1 and 8.2. This conformational change, involving the loop 85-90, provides a structural basis for a variety of pH-dependent chemical, physical, and spectroscopic phenomena, collectively known as the Tanford transition.<ref>PMID:9760236</ref>
The structures of the trigonal crystal form of bovine beta-lactoglobulin variant A at pH 6.2, 7.1, and 8.2 have been determined by X-ray diffraction methods at a resolution of 2.56, 2. 24, and 2.49 A, respectively. The glutamate side chain of residue 89 is buried at pH 6.2 and becomes exposed at pH 7.1 and 8.2. This conformational change, involving the loop 85-90, provides a structural basis for a variety of pH-dependent chemical, physical, and spectroscopic phenomena, collectively known as the Tanford transition.<ref>PMID:9760236</ref>
it was found that the stereochemical environment of Tyr42 changes significantly with pH variation between pH 7 and pH 8. This may provide a structural explanation for an as yet unexplained feature of the Tanford transition, namely the increase in exposure of a tyrosine residue.<ref>PMID:11168385</ref>
 
It was found that the stereochemical environment of Tyr42 changes significantly with pH variation between pH 7 and pH 8. This may provide a structural explanation for an as yet unexplained feature of the Tanford transition, namely the increase in exposure of a tyrosine residue.<ref>PMID:11168385</ref>


Dimeric Lactoglobulin molecules exist in the open conformation at basic pH, whereas they exist in the closed conformation at acidic pH, after undergoing Tanford transition around neutral pH.<ref>PMID:17932936</ref>
Dimeric Lactoglobulin molecules exist in the open conformation at basic pH, whereas they exist in the closed conformation at acidic pH, after undergoing Tanford transition around neutral pH.<ref>PMID:17932936</ref>
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Cross-linking the free thiol groups of beta-LG by heating (100 degrees C for 2 min), or chemically modifying the beta-LG by carboxymethylation to block the thiol groups resulted in a substantial loss of antioxidant activity. The data suggest that Cys-121 plays an essential role in the antioxidant nature of beta-LG.<ref>PMID:17235131</ref>
Cross-linking the free thiol groups of beta-LG by heating (100 degrees C for 2 min), or chemically modifying the beta-LG by carboxymethylation to block the thiol groups resulted in a substantial loss of antioxidant activity. The data suggest that Cys-121 plays an essential role in the antioxidant nature of beta-LG.<ref>PMID:17235131</ref>


===how the protein function===
include chemical structure of any relevant ligands, inhibitors, or important states in the reaction pathway.
==Other 3D Structures of beta-Lactoglobulin==
[[8tim]], [[1tim]], [[1tpb]], [[1tpc]], [[1tpw]] – cTIM – chicken<br />
[[1amk]] – LmTIM – ''Leishmania mexicana''<br />




===complexes with ...===


[[1beb]] - yTIM + 2-phosphoglycolate<br />
=== other β-Lactoglobulin 3D Structures and complexes ===


[[1b8e]] - Crystal structure of the Bovine beta-Lactoglobulin (Isoforms A and B) in orthorombic space group
[[1qg5]] - Crystal structure of the Bovine beta-Lactoglobulin (Isoforms A)
[[1beb]] - Bovine beta-Lactoglobulin, Lattice X
[[1cj5]] - Bovine beta-Lactoglobulin A
[[1gx8]] - Bovine beta-Lactoglobulin complexed with Retinol, Trigonal Lattice Z
[[1gx9]] - Bovine beta-Lactoglobulin complexed with Retinoic acid, Trigonal Lattice Z
[[1gxa]] - Bovine beta-Lactoglobulin complexed with Retinol and Palmitic acid, Trigonal Lattice Z
[[1b0o]] - Bovine beta-Lactoglobulin complexed with Palmitate, Lattice Z
[[1bsy]] [[2blg]] [[3blg]] - Structural Basis of the Tanford Transitioon of Bovine beta-Lactoglobulin from crystal structures at 3 ph values


== References ==
== References ==
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