1H, 13C and 15N assignments and chemical shift-derived secondary structure of intestinal fatty acid-binding protein

Summary Sequence-specific ¹H, ¹³C and ¹⁵N resonance assignments have been established for rat intestinal fatty acid-binding protein complexed with palmitate (15.4 kDa) at pH 7.2 and 37°C. The resonance assignment strategy involved the concerted use of seven 3D triple-resonance expriments (CC-TOCSY, HCCH-TOCSY, HNCO, HNCA, ¹⁵N-TOCSY-HMQC, HCACO and HCA(CO)N). A central feature of this strategy was the concurrent assignment of both backbone and side-chain aliphatic atoms, which was critical for overcoming ambiguities in the assignment process. The CC-TOCSY experiment provided the unambiguous links between the side-chain spin systems observed in HCCH-TOCSY and the backbone correlations observed in the other experiments. Assignments were established for 124 of the 131 residues, although 6 of the 124 had missing amide ¹H resonances, presumably due to rapid exchange with solvent under these experimental conditions. The assignment database was used to determine the solution secondary structure of the complex, based on chemical shift indices for the ¹H, ¹³C, ¹³C and ¹³CO atoms. Overall, the secondary structure agreed well with that determined by X-ray crystallography [Sacchettini et al. (1989) J. Mol. Biol., 208, 327–339], although minor differences were observed at the edges of secondary structure elements.     

1H, 15N, 13C resonance assignments of the reduced and active form of human Protein Tyrosine Phosphatase, PRL-1

Phosphatase of regenerating liver-1 (PRL-1) is a novel target for potentially treating cancer metastases. Although its specific biochemical role in these processes has yet to be delineated, considerable evidence suggests the phosphatase activity of PRL-1 is required for promoting cancer and metastasis. PRL-1 belongs to the protein tyrosine phosphatase (PTPase) family and functions using the CX₅R consensus active site motif. Like other PTPases, PRL-1 is inhibited by oxidation at its active site Cys, however, disulfide bond formation occurs unusually readily in wild-type PRL-1. Chemical shift assignments are available for oxidized wild type, but numerous, substantial changes are observed in the spectra upon reduction. Because the reduced form is active, we sought to identify a stable mutant that would resist oxidation and be useful for facilitating drug screening and development using NMR-based assays. We present here NMR assignments for a full-length, reduced and active form of PRL-1, PRL-1-C170S-C171S, that is well suited for this purpose.     

Sequence-specific 1H, 13C, and 15N resonance assignments of GRP1 PH domain

The carboxy-terminal pleckstrin homology (PH) domain recruits GRP1 to the plasma membrane through the specific binding to phosphatidylinositol 3,4,5-trisphosphate [PtdIns(3,4,5)P₃]. Here, we describe backbone and side chain assignments of the GRP1 PH domain determined by triple resonance experiments. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Backbone and side-chain 1H, 13C, 15N resonance assignments of rat lipocalin2

Lipocalin2 plays an important role in the innate immune system. In this article we report the backbone and side-chain resonance assignments of rat lipocalin2 (rLcn2). These assignments provide a basis for determining the structure and dynamics of rLcn2. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.