1oca: Difference between revisions

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HUMAN CYCLOPHILIN A, UNLIGATED, NMR, 20 STRUCTURES

OverviewOverview

The nuclear magnetic resonance (NMR) solution structure of free, unligated cyclophilin A (CypA), which is an 18 kDa protein from human T-lymphocytes that was expressed in Escherichia coli for the present study, was determined using multidimensional heteronuclear NMR techniques. Sequence-specific resonance assignments for 99.5% of all backbone amide protons and non-labile hydrogen atoms provided the basis for collection of an input of 4101 nuclear Overhauser enhancement (NOE) upper distance constraints and 371 dihedral angle constraints for distance geometry calculations and energy minimization with the programs DIANA and OPAL. The average RMSD values of the 20 best energy-refined NMR conformers relative to the mean coordinates are 0.49 A for the backbone atoms and 0.88 A for all heavy atoms of residues 2 to 165. The molecular architecture includes an eight-stranded antiparallel beta-barrel that is closed by two amphipathic alpha-helices. Detailed comparisons with the crystal structure of free CypA revealed subtle but significant conformational differences that can in most cases be related to lattice contacts in the crystal structure. 15N spin relaxation times and NMR lineshape analyses for CypA in the free form and complexed with cyclosporin A (CsA) revealed transitions of polypeptide loops surrounding the ligand-binding site from locally flexible conformations in the free protein, some of which include well-defined conformational equilibria, to well-defined spatial arrangements in the CypA-CsA complex. Compared to the crystal structure of free CypA, where the ligand-binding area is extensively involved in lattice contacts, the NMR structure presents a highly relevant reference for studies of changes in structure and internal mobility of the binding pocket upon ligand binding, and possible consequences of this conformational variability for calcineurin recognition by the CypA-CsA complex.

About this StructureAbout this Structure

1OCA is a Single protein structure of sequence from Homo sapiens. Active as Peptidylprolyl isomerase, with EC number 5.2.1.8 Full crystallographic information is available from OCA.

ReferenceReference

The NMR solution conformation of unligated human cyclophilin A., Ottiger M, Zerbe O, Guntert P, Wuthrich K, J Mol Biol. 1997 Sep 12;272(1):64-81. PMID:9299338

Page seeded by OCA on Thu Feb 21 14:16:05 2008

Proteopedia Page Contributors and Editors (what is this?)Proteopedia Page Contributors and Editors (what is this?)

OCA

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 '''HUMAN CYCLOPHILIN A, UNLIGATED, NMR, 20 STRUCTURES'''<br />
 ==Overview==
-The nuclear magnetic resonance (NMR) solution structure of free, unligated, cyclophilin A (CypA), which is an 18 kDa protein from human T-lymphocytes, that was expressed in Escherichia coli for the present study, was, determined using multidimensional heteronuclear NMR techniques., Sequence-specific resonance assignments for 99.5% of all backbone amide, protons and non-labile hydrogen atoms provided the basis for collection of, an input of 4101 nuclear Overhauser enhancement (NOE) upper distance, constraints and 371 dihedral angle constraints for distance geometry, calculations and energy minimization with the programs DIANA and OPAL. The, average RMSD values of the 20 best energy-refined NMR conformers relative, to the mean coordinates are 0.49 A for the backbone atoms and 0.88 A for, all heavy atoms of residues 2 to 165. The molecular architecture includes, an eight-stranded antiparallel beta-barrel that is closed by two, amphipathic alpha-helices. Detailed comparisons with the crystal structure, of free CypA revealed subtle but significant conformational differences, that can in most cases be related to lattice contacts in the crystal, structure. 15N spin relaxation times and NMR lineshape analyses for CypA, in the free form and complexed with cyclosporin A (CsA) revealed, transitions of polypeptide loops surrounding the ligand-binding site from, locally flexible conformations in the free protein, some of which include, well-defined conformational equilibria, to well-defined spatial, arrangements in the CypA-CsA complex. Compared to the crystal structure of, free CypA, where the ligand-binding area is extensively involved in, lattice contacts, the NMR structure presents a highly relevant reference, for studies of changes in structure and internal mobility of the binding, pocket upon ligand binding, and possible consequences of this, conformational variability for calcineurin recognition by the CypA-CsA, complex.
+The nuclear magnetic resonance (NMR) solution structure of free, unligated cyclophilin A (CypA), which is an 18 kDa protein from human T-lymphocytes that was expressed in Escherichia coli for the present study, was determined using multidimensional heteronuclear NMR techniques. Sequence-specific resonance assignments for 99.5% of all backbone amide protons and non-labile hydrogen atoms provided the basis for collection of an input of 4101 nuclear Overhauser enhancement (NOE) upper distance constraints and 371 dihedral angle constraints for distance geometry calculations and energy minimization with the programs DIANA and OPAL. The average RMSD values of the 20 best energy-refined NMR conformers relative to the mean coordinates are 0.49 A for the backbone atoms and 0.88 A for all heavy atoms of residues 2 to 165. The molecular architecture includes an eight-stranded antiparallel beta-barrel that is closed by two amphipathic alpha-helices. Detailed comparisons with the crystal structure of free CypA revealed subtle but significant conformational differences that can in most cases be related to lattice contacts in the crystal structure. 15N spin relaxation times and NMR lineshape analyses for CypA in the free form and complexed with cyclosporin A (CsA) revealed transitions of polypeptide loops surrounding the ligand-binding site from locally flexible conformations in the free protein, some of which include well-defined conformational equilibria, to well-defined spatial arrangements in the CypA-CsA complex. Compared to the crystal structure of free CypA, where the ligand-binding area is extensively involved in lattice contacts, the NMR structure presents a highly relevant reference for studies of changes in structure and internal mobility of the binding pocket upon ligand binding, and possible consequences of this conformational variability for calcineurin recognition by the CypA-CsA complex.
 ==About this Structure==
-OCA is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Active as [http://en.wikipedia.org/wiki/Peptidylprolyl_isomerase Peptidylprolyl isomerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=5.2.1.8 5.2.1.8] Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1OCA OCA].
+OCA is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Active as [http://en.wikipedia.org/wiki/Peptidylprolyl_isomerase Peptidylprolyl isomerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=5.2.1.8 5.2.1.8] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1OCA OCA].
 ==Reference==
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 [[Category: peptidyl-prolyl cis-trans isomerase]]
-''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov 12 18:31:28 2007''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:16:05 2008''