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The N-end rule states that the half-life of a protein is determined by the nature of its amino-terminal residue. Eukaryotes and prokaryotes use N-terminal destabilizing residues as a signal to target proteins for degradation by the N-end rule pathway. In eukaryotes an E3 ligase, N-recognin, recognizes N-end rule substrates and mediates their ubiquitination(More)
The NMR structures of the recombinant human prion protein, hPrP(23-230), and two C-terminal fragments, hPrP(90-230) and hPrP(121-230), include a globular domain extending from residues 125-228, for which a detailed structure was obtained, and an N-terminal flexibly disordered "tail." The globular domain contains three alpha-helices comprising the residues(More)
The NMR structure of the globular domain of the human prion protein (hPrP) with residues 121-230 at pH 7.0 shows the same global fold as the previously published structure determined at pH 4.5. It contains three alpha-helices, comprising residues 144-156, 174-194, and 200-228, and a short anti-parallel beta-sheet, comprising residues 128-131 and 161-164.(More)
Human UDP-d-xylose:proteoglycan core protein beta-d-xylosyltransferase (EC 2.4.2.26, XT-I) initiates the biosynthesis of glycosaminoglycan chains in proteoglycans by transferring xylose from UDP-xylose to specific serine residues of the core protein. Based on the partial amino acid sequence of the purified enzyme from human JAR choriocarcinoma cell culture(More)
An efficient method is presented for the production of intact mammalian prion proteins and partial sequences thereof. As an illustration we describe the production of polypeptides comprising residues 23-231, 81-231, 90-231 and 121-231 of the human prion protein (hPrP). Polypeptides were expressed as histidine tail fusion proteins into inclusion bodies in(More)
We have analysed the conformational states of barnase that are bound by the molecular chaperones GroEL and SecB. Line broadening in the NMR spectra of barnase in the presence of chaperone indicates binding of the native state of barnase to both GroEL and SecB, with a dissociation constant of > 3 x 10(-4) M for the GroEL-native barnase complex. GroEL and(More)
Transmissible spongiform encephalopathies (TSE) or "prion diseases" have been related to the "protein-only hypothesis", which suggests that the "scrapie form (PrPSc)" of the prion protein (PrP) is the TSE infectious agent. The nmr structure of the ubiquitous benign cellular form of PrP (PrPC) consists of a globular domain of residues 126-231 with three(More)
The NMR structures of the recombinant 217-residue polypeptide chain of the mature bovine prion protein, bPrP(23-230), and a C-terminal fragment, bPrP(121-230), include a globular domain extending from residue 125 to residue 227, a short flexible chain end of residues 228-230, and an N-terminal flexibly disordered "tail" comprising 108 residues for the(More)
A monomeric peptide fragment of GroEL, consisting of residues 191-376, is a mini-chaperone with a functional chaperoning activity. We have solved the crystal structure at 1.7 A resolution of GroEL(191-376) with a 17-residue N-terminal tag. The N-terminal tag of one molecule binds in the active site of a neighboring molecule in the crystal. This appears to(More)
The chaperonin GroEL is a large complex composed of 14 identical 57-kDa subunits that requires ATP and GroES for some of its activities. We find that a monomeric polypeptide corresponding to residues 191 to 345 has the activity of the tetradecamer both in facilitating the refolding of rhodanese and cyclophilin A in the absence of ATP and in catalyzing the(More)