1xbl
From Proteopedia
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NMR STRUCTURE OF THE J-DOMAIN (RESIDUES 2-76) IN THE ESCHERICHIA COLI N-TERMINAL FRAGMENT (RESIDUES 2-108) OF THE MOLECULAR CHAPERONE DNAJ, 20 STRUCTURES
Overview
The recombinant N-terminal 107-amino acid polypeptide fragment 2-108 of, the DnaJ molecular chaperone of Escherichia coli, which contains the, J-domain (residues 2 to 76) and the Gly/Phe-rich region (residues 77 to, 108), was uniformly labeled with nitrogen-15 and carbon-13. The complete, NMR solution structure of the J-domain was determined with the program, DIANA on the basis of 682 nuclear Overhauser enhancement (NOE) upper, distance limits and 180 dihedral angle constraints. It contains three, well-defined helices comprising residues 6 to 10, 18 to 32 and 41 to 57, and a fourth helix, consisting of residues 61 to 68, which is well defined, as a regular secondary structure but for which the location relative to, the remainder of the molecule is not precisely determined. The helices II, and III form an antiparallel helical coiled-coil. Helix I is approximately, parallel to the plane defined by the helices II and III and runs from the, carboxy-terminal end of the helix III to the center of helix II. Helix IV, is positioned near the carboxy-terminal end of helix III and is on the, same side of the coiled coil as helix I, but it is oriented approximately, perpendicular to the plane of the helices II and III. This novel, alpha-protein topology leads to formation of a hydrophobic core involving, side-chains of all four helices. A strong correlation is seen between the, extent of sequence-conservation of hydrophobic residues in the family of, J-domain homologues, and the structural organization of the hydrophobic, core in these proteins. The residues which have key roles for the, specificity of the interaction of DnaJ-like proteins with their, corresponding Hsp70 counterparts are located on the outer surfaces of the, helices II and III, and in the loop connecting these two helices., Measurements of backbone amide proton exchange rates, 15N spin relaxation, times and heteronuclear 15N {1H} NOEs provided additional insights into, local conformational equilibria and internal rate processes in, DnaJ(2-108). In the Gly/Phe-rich region, which is poorly ordered in the, NMR solution structure and does not form a globular core, the polypeptide, segment 90 to 103 differs from the segments 77 to 89 and 104 to 108 by, reduced local flexibility. Considering that this same segment shows, sequence conservation with corresponding segments in the Gly/Phe-rich, regions of other DnaJ-like proteins, its reduced flexibility may be, directly linked to the formation of the ternary DnaJ-DnaK-polypeptide, complex.
About this Structure
1XBL is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
NMR structure of the J-domain and the Gly/Phe-rich region of the Escherichia coli DnaJ chaperone., Pellecchia M, Szyperski T, Wall D, Georgopoulos C, Wuthrich K, J Mol Biol. 1996 Jul 12;260(2):236-50. PMID:8764403
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