2rs4

NMR structure of stereo-array isotope labelled (SAIL) peptidyl-prolyl cis-trans isomerase from E. coli (EPPIb)

spinqualitylabelsall models 2rs4 Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2rs4 is a 1 chain structure with sequence from Escherichia coli K-12. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance. Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function PPIB_ECOLI PPIases accelerate the folding of proteins. It catalyzes the cis-trans isomerization of proline imidic peptide bonds in oligopeptides. Publication Abstract from PubMed We recently developed new NMR methods for monitoring the hydrogen exchange rates of tyrosine hydroxyl (Tyr-OH) and cysteine sulfhydryl (Cys-SH) groups in proteins. These methods facilitate the identification of slowly exchanging polar side-chain protons in proteins, which serve as sources of NOE restraints for protein structure refinement. Here, we have extended the methods for monitoring the hydrogen exchange rates of the OH groups of serine (Ser) and threonine (Thr) residues in an 18.2 kDa protein, EPPIb, and thus demonstrated the usefulness of NOE restraints with slowly exchanging OH protons for refining the protein structure. The slowly exchanging Ser/Thr-OH groups were readily identified by monitoring the (13)C(beta)-NMR signals in an H(2)O/D(2)O (1:1) mixture, for the protein containing Ser/Thr residues with (13)C, (2)H-double labels at their beta carbons. Under these circumstances, the OH groups exist in equilibrium between the protonated and deuterated isotopomers, and the (13)C(beta) peaks of the two species are resolved when their exchange rate is slower than the time scale of the isotope shift effect. In the case of EPPIb dissolved in 50 mM sodium phosphate buffer (pH 7.5) at 40 degrees C, one Ser and four Thr residues were found to have slowly exchanging hydroxyl groups (k(ex) < approximately 40 s(-1)). With the information for the slowly exchanging Ser/Thr-OH groups in hand, we could collect additional NOE restraints for EPPIb, thereby making a unique and important contribution toward defining the spatial positions of the OH protons, and thus the hydrogen-bonding acceptor atoms. Hydrogen Exchange Study on the Hydroxyl Groups of Serine and Threonine Residues in Proteins and Structure Refinement Using NOE Restraints with Polar Side-Chain Groups.,Takeda M, Jee J, Ono AM, Terauchi T, Kainosho M J Am Chem Soc. 2011 Oct 10. PMID:21955241 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Cyclophilin 3D structures

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