• Title/Summary/Keyword: Membrane Protein

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Backbone 1H, 15N, and 13C Resonance Assignments and Secondary-Structure of Conserved Hypothetical Protein HP0894 from Helicobacter pylori

  • Han, Kyung-Doo;Park, Sung-Jean;Lee, Bong-Jin
    • Molecules and Cells
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    • v.20 no.3
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    • pp.442-445
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    • 2005
  • HP0894 (SwissProt/TrEMBL ID O25554) is an 88-residue conserved hypothetical protein from Helicobacter pylori strain 26695 with a calculated pI of 8.5 and a molecular weight of 10.38 kDa. Proteins with sequence similarity to HP0894 exist in Vibrio choierae, Enterococcus faecalis, Campylobacter jejuni, Streptococcus pneumoniae, Haemophilus influenzae, Escherichia coli O157, etc. Here we report the sequence-specific backbone resonance assignments of HP0894. About 97.5% (418/429) of the HN, N, CO, $C{\alpha}$, $C{\beta}$ resonances of the 88 residues of HP0894 were assigned. On the basis of these assignments, three helical regions and four strand regions were identified using the CSI program. This study is a prerequisite for calculating the solution structure of HP0894, and studying its interaction with its substrates, if any, and/or with other proteins.

Chemistry and Biology of Ras Farnesyltransferase

  • Cho, Kwang-Nym;Lee, Kee-In
    • Archives of Pharmacal Research
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    • v.25 no.6
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    • pp.759-769
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    • 2002
  • Mutated forms of ras are found in many human tumors and the rate of incidence is significantly higher in colon and pancreatic cancers. The protein product from the ras oncogene is a small G-protein, $p21^{ras}{\;}(Ras)$ that is known to playa key role in the signal transduction cascade and cell differentiation and proliferation. Mutated Ras is unable to regulate itself and remains constantly activated, leading to uncontrolled cell growth. The function of Ras in signal transduction requires its location near the growth factor receptor at the cell membrane. However, Ras does not have a transmembrane domain. Ras requires farnesylation to increase its hydrophobicity and subsequent plasma membrane association for its transforming activity. This key post-translational modification is catalyzed by the enzyme Ras farnesyltransferase (FTase), which transfers a farnesyl group from farnesylpyrophosphate to the C-terminal cysteine of the Ras protein. The requirement has focused attention on FTase as a target for therapeutic intervention. Selective inhibition of FTase will prevent Ras protein from association with the plasma membrane, leading to a disruption of oncogenic Ras function.

Construction of 1H-15N Double Resonance Solid-State NMR Probe for Membrane Proteins in Aligned Bicelles

  • Park, Tae-Joon;Kim, Ji-Sun;Um, Seung-Hoon;Kim, Yong-Ae
    • Bulletin of the Korean Chemical Society
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    • v.31 no.5
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    • pp.1187-1191
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    • 2010
  • $^1H-^{15}N$ heteronuclear dipolar coupling solid-state NMR experiments on lipid bilayer or bicelle samples are very useful for the structural studies of membrane proteins. However, to study these biological samples using solid-state NMR, a specific probe with high efficiency and high capability is required. In this paper, we describe the optimized design, construction, and efficiency of a 400 MHz wide-bore $^1H-^{15}N$ solid-state NMR probe with 5-mm solenoidal rf coil for high power, multi-pulse sequence experiments, such as 2D PISEMA or 2D SAMMY.

TM4SF5-mediated protein-protein networks and tumorigenic roles

  • Lee, Jung Weon
    • BMB Reports
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    • v.47 no.9
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    • pp.483-487
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    • 2014
  • Transmembrane 4 L six family member 5 (TM4SF5), as a membrane glycoprotein with 4 transmembrane domains, is similar to the tetraspanins in terms of membrane topology and plays important roles in tumorigenesis and tumor metastasis. Especially, TM4SF5 appears to form a massive protein-protein complex consisting of diverse membrane proteins and/or receptors in addition to cytosolic signaling molecules to regulate their signaling activities during the pathological processes. TM4SF5 is shown to interact with integrins ${\alpha}2$, ${\alpha}5$, and ${\beta}1$, EGFR, IL6R, CD151, focal adhesion kinase (FAK), and c-Src. This review focuses on the significance of the interactions with regards to TM4SF5-positive tumorigenesis and metastasis.

Immunogenicity of Recombinant Outer Membrane Protein H from Pasteurella multocida (재조합 파스튜렐라 외막 단백질 H의 면역원성 검정)

  • Lee Jeong-Min
    • Microbiology and Biotechnology Letters
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    • v.34 no.3
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    • pp.273-277
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    • 2006
  • To investigate the antigenicity and protective immunity of outer membrane protein H (OmpH) in Pasteurella multocida D:4, the recombinant OmpH protein was produced in Escherichia coli. The truncated and Trx-fused form of recombinant OmpH (53 kDa) was purified, and used as an antigen in the immunization and challenge experiment. The immunized mice with the recombinant OmpH produced a high-titer antibody, and had protective immunity against P. multocida as same level as the mice immunized with formalin-killed whole cell.

Immunization with Major Outer Membrane Protein of Vibrio vulnificus Elicits Protective Antibodies in a Murine Model

  • Jung Cho-Rok;Park Min-Jung;Heo Moon-Soo
    • Journal of Microbiology
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    • v.43 no.5
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    • pp.437-442
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    • 2005
  • Sera from rabbits were infected with Vibrio vulnificus containing an antibody against major outer membrane protein (MOMP). MOMP of V. vulnificus ATCC 27562 were isolated and purified by Sarkosyl and TritonX-100 dual treatment. Molecular size of MOMP was identified as 36-kDa on $13\%$ SDS-PAGE. The sequence of the first 26 amino acid residues from the N-terminal end of the protein is AELYNQDGTSLDMGGRAEARLSMKDG, which is a perfect match with OmpU of V. vulnificus CMCP6 and YJ016. MOMP specific IgM and IgG were investigated in groups of mice. The group of mice immunized with MOMP and Alum showed higher levels of IgG2b than the group immunized with only MOMP. Vaccination with MOMP resulted in protective antibodies in the mouse infection experiment.

Protein and RNA Quality Control by Autophagy in Plant Cells

  • Yoon, Seok Ho;Chung, Taijoon
    • Molecules and Cells
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    • v.42 no.4
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    • pp.285-291
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    • 2019
  • Eukaryotic cells use conserved quality control mechanisms to repair or degrade defective proteins, which are synthesized at a high rate during proteotoxic stress. Quality control mechanisms include molecular chaperones, the ubiquitin-proteasome system, and autophagic machinery. Recent research reveals that during autophagy, membrane-bound organelles are selectively sequestered and degraded. Selective autophagy is also critical for the clearance of excess or damaged protein complexes (e.g., proteasomes and ribosomes) and membrane-less compartments (e.g., protein aggregates and ribonucleoprotein granules). As sessile organisms, plants rely on quality control mechanisms for their adaptation to fluctuating environments. In this mini-review, we highlight recent work elucidating the roles of selective autophagy in the quality control of proteins and RNA in plant cells. Emphasis will be placed on selective degradation of membrane-less compartments and protein complexes in the cytoplasm. We also propose possible mechanisms by which defective proteins are selectively recognized by autophagic machinery.

Deciphering the molecular mechanisms underlying the plasma membrane targeting of PRMT8

  • Park, Sang-Won;Jun, Yong-Woo;Choi, Ha-Eun;Lee, Jin-A;Jang, Deok-Jin
    • BMB Reports
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    • v.52 no.10
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    • pp.601-606
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    • 2019
  • Arginine methylation plays crucial roles in many cellular functions including signal transduction, RNA transcription, and regulation of gene expression. Protein arginine methyltransferase 8 (PRMT8), a unique brain-specific protein, is localized to the plasma membrane. However, the detailed molecular mechanisms underlying PRMT8 plasma membrane targeting remain unclear. Here, we demonstrate that the N-terminal 20 amino acids of PRMT8 are sufficient for plasma membrane localization and that oligomerization enhances membrane localization. The basic amino acids, combined with myristoylation within the N-terminal 20 amino acids of PRMT8, are critical for plasma membrane targeting. We also found that substituting Gly-2 with Ala [PRMT8(G2A)] or Cys-9 with Ser [PRMT8(C9S)] induces the formation of punctate structures in the cytosol or patch-like plasma membrane localization, respectively. Impairment of PRMT8 oligomerization/dimerization by C-terminal deletion induces PRMT8 mis-localization to the mitochondria, prevents the formation of punctate structures by PRMT8(G2A), and inhibits PRMT8(C9S) patch-like plasma membrane localization. Overall, these results suggest that oligomerization/dimerization plays several roles in inducing the efficient and specific plasma membrane localization of PRMT8.

Simulation Methods for Prediction of Membrane Protein Structure

  • Son, Hyeon-S.
    • Proceedings of the Korean Biophysical Society Conference
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    • 1998.06a
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    • pp.10-10
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    • 1998
  • IMPs are important to cells in functions such as transport, energy transduction and signalling. Three dimensional molecular structures of such proteins at atomic level are needed to understand such processes. Prediction of such structures (and functions) is necessary especially because there are only a small number of membrane protein structures determined in atomic resolution.(omitted)

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Specific Detection of Xanthomonas oryzae pv. oryzicola in Infected Rice Plant by Use of PCR Assay Targeting a Membrane Fusion Protein Gene

  • Kang, Man-Jung;Shim, Jae-Kyung;Cho, Min-Seok;Seol, Young-Joo;Hahn, Jang-Ho;Hwang, Duk-Ju;Park, Dong-Suk
    • Journal of Microbiology and Biotechnology
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    • v.18 no.9
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    • pp.1492-1495
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    • 2008
  • Successful control of Xanthomonas oryzae pv. oryzicola, the causal agent of bacterial leaf streak, requires a specific and reliable diagnostic tool. A pathovar-specific PCR assay was developed for the rapid and accurate detection ofthe plant pathogenic bacterium Xanthomonas oryzae pv. oryzicola in diseased plant. Based on differences in a membrane fusion protein gene of Xanthomonas oryzae pv. oryzicola and other microorganisms, which was generated from NCBI (http://www.ncbi.nlm.nih.gov/) and CMR (http://cmr.tigr.org/) BLAST searches, one pair of pathovar-specific primers, XOCMF/XOCMR, was synthesized. Primers XOCMF and XOCMR from a membrane fusion protein gene were used to amplity a 488-bp DNA fragment. The PCR product was only produced from 4 isolates of Xanthomonas oryzae pv. oryzicola among 37 isolates of other pathovars and species of Xanthomonas, Pectobacterium, Pseudomonas, Burkholderia, Escherichia coli, and Fusarium oxysporum f.sp. dianthi. The results suggested that the assay detected the pathogen more rapidly and accurately than standard isolation methods.