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211.
212.
James M. Chen Grace Lee Paul W. Brandt-Rauf Randall B. Murphy Shalom Rackovsky Matthew R. Pincus 《Journal of Protein Chemistry》1990,9(5):543-547
The predicted conformation and position of the central transforming region (residues 55–67) of the p21 protein are compared with the conformation and position of this segment in a recently determined X-ray crystal structure of residues 1–166 of this protein in the activated state bound to a nonhydrolyzable GTP derivative. We previously predicted that this segment of the protein would adopt a roughly extended conformation from Ile 55-Thr 58, a reverse turn at Ala 59-Gln 61, followed by an -helix from Glu 62-Met 67. We further predicted that this region of the activated protein occupies a position that is virtually identical to corresponding regions in the homologous purine nucleotide-binding proteins, bacterial elongation factor (EF-tu), and adenylate kinase (ADK). We find that there is a close correspondence between the conformation and position of our predicted structure and those found in the X-ray crystal structure. A mechanism for activation of the protein is proposed and is corroborated by X-ray crystallographic data. 相似文献
213.
Dianne M. Rausch Deborah L. Lewis Jeffrey L. Barker Lee E. Eiden 《Cellular and molecular neurobiology》1990,10(2):237-255
1. Recombinant retroviruses were used to introduce a temperature-sensitive v-src gene and oncogenic c-Ha-ras into PC12 cells, and stable cell lines expressing these genes were established. 2. As previously reported, expression of v-src (Alema et al., 1985) or c-Ha-ras (Noda et al., 1985) in PC12 cells results in neurite outgrowth resembling that induced by NGF. We report here that v-src but not oncogenic c-Ha-ras induces a stable morphologic neuronal differentiation similar to treatment with NGF. Oncogenic c-Ha-ras-induced neurite outgrowth is not stable with long-term culture, rather the cells revert to an undifferentiated morphology with altered cell cycle kinetics. 3. The stable neuronal phenotype induced by v-src and NGF is characterized by the functional expression of dihydropyridine-insensitive calcium currents. 相似文献
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Chuen-Shang C. Wu Junichi Hasegawa Andrew P. Smith Horace H. Loh Nancy M. Lee Jen Tsi Yang 《Journal of Protein Chemistry》1990,9(1):3-7
Based on circular dichroism (CD) and the sequence-predictive method, the opioid-binding cell adhesion molecule (OBCAM) consisted of one half -sheets and one fourth -helices. This is consistent with significant sequence homology of the protein to several members of the immunoglobulin (Ig) superfamily, particularly cell adhesion molecules, which are rich in -sheets. Hydropathy analysis suggests that hydrophobic and hydrophilic regions were evenly distributed along the sequence, but the NH2- and COOH-termini were hydrophobic. Hydrophobic moments and Fourier-transform amphipathic analyses further suggest that residues 23–30 and 83–93 were amphiphathie -sheets. The overall conformation of OBCAM was unaltered by adding linoleic acid, which is required for opioid ligand binding. 相似文献
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218.
Roger V. Lebo Lee A. Anderson Salvatore DiMauro Eric Lynch Peter Hwang Robert Fletterick 《Human genetics》1990,86(1):17-24
Summary When probes throughout the McArdle disease (myophosphorylase) gene region were used to search for DNA polymorphisms, only an MspI polymorphism was found in 94 enzyme-probe combinations. Along with an insertion/deletion polymorphism more 3 to the gene locus, these polymorphisms will be informative in 75% of at-risk patients. These results contrast strikingly to the six polymorphic sites detected in 15 enzyme-probe combinations in the homologous Her's disease (liver phosphorylase) gene region. This single MspI polymorphic site includes a CpG sequence of known increased mutability suggesting that DNA regions with rare polymorphisms will have most polymorphic sites at sequences with enhanced mutability. Fluorescence in situ hybridization sublocalized this gene to proximal band 11q13, establishing a point of cross-reference between the physical and genetic maps. 相似文献
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Mansoor N. Saleh Albert F. LoBuglio Richard H. Wheeler Kimberly J. Rogers Amy Haynes Jeannette Y. Lee M. B. Khazaeli 《Cancer immunology, immunotherapy : CII》1990,32(3):185-190
Summary A group of 15 patients with metastatic colorectal adenocarcinoma received a combination of interferon (0.1 mg/m2, days 1–15) and the murine monoclonal antibody 17-1A (400 mg, days 5, 7, 9 and 12). The treatment was tolerated with minimal toxicity. Of the 14 evaluable patients, 13 developed human antibody to murine 17-1A, with 11 patients demonstrating antibody to the variable region of 17-1A (anti-idiotype). Antibody to the variable region was inhibited by 17-1A but not by mouse immunoglobulin. Sera from patients with substantial anti-idiotype reactivity were capable of inhibiting the binding of murine 17-1A to antigen expressing LS174-T cells thus indicating the presence of antibody directed against the 17-1A combining site (mirror-image anti-idiotype). The median survival of the whole group was 56 weeks and there was no correlation between clinical response/survival and the development of anti-idiotype antibody.Supported by the Veterans Administration Medical Center and by Public Health Services grant CA 45 232 from the National Cancer Institute, National Institutes of Health, Department of Health and Human Services 相似文献