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| | {{STRUCTURE_1gnb| PDB=1gnb | SCENE= }} | | {{STRUCTURE_1gnb| PDB=1gnb | SCENE= }} |
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| - | '''DETERMINATION OF THE SOLUTION STRUCTURE OF THE PEPTIDE HORMONE GUANYLIN: OBSERVATION OF A NOVEL FORM OF TOPOLOGICAL STEREOISOMERISM'''
| + | ===DETERMINATION OF THE SOLUTION STRUCTURE OF THE PEPTIDE HORMONE GUANYLIN: OBSERVATION OF A NOVEL FORM OF TOPOLOGICAL STEREOISOMERISM=== |
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| - | ==Overview==
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| - | Guanylin is a 15 amino acid mammalian hormone containing two disulfide bonds. Guanylin shares sequence similarity with the bacterial heat-stable enterotoxin (STa) and is capable of binding to and stimulating the STa guanylyl cyclase receptor. Biologically active peptides have been prepared by two methods: (1) enzymatic treatment of a 99 residue proprotein (denoted proguanylin) expressed in Escherichia coli and (2) solid-phase chemical synthesis. Although both sources yield material that is pure by high-performance liquid chromatography and mass spectrometry, analysis by nuclear magnetic resonance (NMR) indicates that peptides from both sources contain two conformationally distinct species present in a 1:1 ratio. The chemical shift differences between the two species are large, allowing unambiguous sequential NMR assignments to be made for both sets of resonances. Exchange between the two forms was not observed even at 70 degrees C. Structural restraints have been generated from nuclear Overhauser effects and scalar coupling constants and used to calculate structures for both forms using distance geometry and restrained energy minimization. The resulting structures for the first isoform are well defined (root-mean-square deviation from the average structure for backbone atoms of 0.47 A) and adopt a right-handed spiral conformation, similar to that observed for heat stable enterotoxin. The second isoform is less well defined (root-mean-square deviation from the average structure for backbone atoms of 1.07 A) but clearly adopts a very different fold consisting of a left-hand spiral. The differences in structure suggest that the two forms may have very different affinities toward the STa receptor. The observation of such isomerism has important implications for the common practice of introducing multiple disulfide bonds into small peptides to limit conformational flexibility and enhance bioactivity.
| + | The line below this paragraph, {{ABSTRACT_PUBMED_7947768}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 7947768 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_7947768}} |
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| | ==About this Structure== | | ==About this Structure== |
| - | 1GNB is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1GNB OCA]. | + | 1GNB is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1GNB OCA]. |
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| | ==Reference== | | ==Reference== |
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| | [[Category: Skelton, N J.]] | | [[Category: Skelton, N J.]] |
| | [[Category: Hormone]] | | [[Category: Hormone]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 17:46:40 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 1 05:33:06 2008'' |
Revision as of 02:33, 1 July 2008
Template:STRUCTURE 1gnb
DETERMINATION OF THE SOLUTION STRUCTURE OF THE PEPTIDE HORMONE GUANYLIN: OBSERVATION OF A NOVEL FORM OF TOPOLOGICAL STEREOISOMERISM
Template:ABSTRACT PUBMED 7947768
About this Structure
1GNB is a Single protein structure of sequence from Homo sapiens. Full experimental information is available from OCA.
Reference
Determination of the solution structure of the peptide hormone guanylin: observation of a novel form of topological stereoisomerism., Skelton NJ, Garcia KC, Goeddel DV, Quan C, Burnier JP, Biochemistry. 1994 Nov 22;33(46):13581-92. PMID:7947768
Page seeded by OCA on Tue Jul 1 05:33:06 2008
