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| - | [[Image:2b3b.gif|left|200px]] | + | {{Seed}} |
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| | {{STRUCTURE_2b3b| PDB=2b3b | SCENE= }} | | {{STRUCTURE_2b3b| PDB=2b3b | SCENE= }} |
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| - | '''Thermus thermophilus Glucose/Galactose Binding Protein With Bound Glucose'''
| + | ===Thermus thermophilus Glucose/Galactose Binding Protein With Bound Glucose=== |
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| - | ==Overview==
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| - | Periplasmic binding proteins (PBPs) comprise a protein superfamily that is involved in prokaryotic solute transport and chemotaxis. These proteins have been used to engineer reagentless biosensors to detect natural or non-natural ligands. There is considerable interest in obtaining very stable members of this superfamily from thermophilic bacteria to use as robust engineerable parts in biosensor development. Analysis of the recently determined genome sequence of Thermus thermophilus revealed the presence of more than 30 putative PBPs in this thermophile. One of these is annotated as a glucose binding protein (GBP) based on its genetic linkage to genes that are homologous to an ATP-binding cassette glucose transport system, although the PBP sequence is homologous to periplasmic maltose binding proteins (MBPs). Here we present the cloning, over-expression, characterization of cognate ligands, and determination of the X-ray crystal structure of this gene product. We find that it is a very stable (apo-protein Tm value is 100(+/- 2) degrees C; complexes 106(+/- 3) degrees C and 111(+/- 1) degrees C for glucose and galactose, respectively) glucose (Kd value is 0.08(+/- 0.03) microM) and galactose (Kd value is 0.94(+/- 0.04) microM) binding protein. Determination of the X-ray crystal structure revealed that this T. thermophilus glucose binding protein (ttGBP) is structurally homologous to MBPs rather than other GBPs. The di or tri-saccharide ligands in MBPs are accommodated in long relatively shallow grooves. In the ttGBP binding site, this groove is partially filled by two loops and an alpha-helix, which create a buried binding site that allows binding of only monosaccharides. Comparison of ttGBP and MBP provides a clear example of structural adaptations by which the size of ligand binding sites can be controlled in the PBP super family.
| + | The line below this paragraph, {{ABSTRACT_PUBMED_16904687}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 16904687 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_16904687}} |
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| | ==About this Structure== | | ==About this Structure== |
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| | [[Category: Periplasmic binding protein]] | | [[Category: Periplasmic binding protein]] |
| | [[Category: Protein-carbohydrate complex]] | | [[Category: Protein-carbohydrate complex]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 19:47:54 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jul 28 15:18:03 2008'' |
Revision as of 12:18, 28 July 2008
Template:STRUCTURE 2b3b
Thermus thermophilus Glucose/Galactose Binding Protein With Bound Glucose
Template:ABSTRACT PUBMED 16904687
About this Structure
2B3B is a Single protein structure of sequence from Thermus thermophilus. Full crystallographic information is available from OCA.
Reference
The crystal structure of a thermophilic glucose binding protein reveals adaptations that interconvert mono and di-saccharide binding sites., Cuneo MJ, Changela A, Warren JJ, Beese LS, Hellinga HW, J Mol Biol. 2006 Sep 15;362(2):259-70. Epub 2006 Aug 10. PMID:16904687
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