• Title, Summary, Keyword: G protein

Search Result 8,055, Processing Time 0.087 seconds

Detection of IgG Using Thiolated Protein G Modified SPR Sensor Chip (Thiolated protein G로 개질된 SPR 센서 칩을 이용한 IgG 검출)

  • Sin, Eun-Jung;Lee, Yeon-Kyung;Sohn, Young-Soo
    • Journal of Sensor Science and Technology
    • /
    • v.20 no.6
    • /
    • pp.434-438
    • /
    • 2011
  • A portable surface plasmon resonance(SPR) based immunosensor using thiolated protein G and protein G was developed for the detection of immunoglobulin G(IgG). The protein G has specific affinity with Fc fragment of IgG and was thiolated by 2-Iminothiolane for introduction of thiol groups. Anti-IgG, bovine serum albumin(BSA), and IgG have been sequently injected after surface modification of gold sensor chip with protein G and thiolated protein G. The output signal was increased with the injection of each protein and the actual signal was measured by subtracting signal of reference channel from signal of sample injected channel. The experimental results showed the higher detection capability of IgG using thiolated protein G compared with protein G. From these results, we can conclude that the current surface modification technique and the portable SPR sensor system can be applied to various immunosensors for diagnosis.

Structural Aspects of GPCR-G Protein Coupling

  • Chung, Ka Young
    • Toxicological Research
    • /
    • v.29 no.3
    • /
    • pp.149-155
    • /
    • 2013
  • G protein-coupled receptors (GPCRs) are membrane receptors; approximately 40% of drugs on the market target GPCRs. A precise understanding of the activation mechanism of GPCRs would facilitate the development of more effective and less toxic drugs. Heterotrimeric G proteins are important molecular switches in GPCR-mediated signal transduction. An agonist-activated receptor interacts with specific sites on G proteins and promotes the release of GDP from the $G{\alpha}$ subunit. Because of the important biological role of the GPCR-G protein coupling, conformational changes in the G protein upon receptor coupling have been of great interest. One of the most important questions was the interface between the GPCR and G proteins and the structural mechanism of GPCR-induced G protein activation. A number of biochemical and biophysical studies have been performed since the late 80s to address these questions; there was a significant breakthrough in 2011 when the crystal structure of a GPCR-G protein complex was solved. This review discusses the structural aspects of GPCR-G protein coupling by comparing the results of previous biochemical and biophysical studies to the GPCR-G protein crystal structure.

A comparison of detection capabilities of anti-IgG immobilizedby protein G and NHS (Protein G와 NHS를 이용하여 고정한 anti-IgG의 검출 성능 비교)

  • Sin, Eun-Jung;Sohn, Young-Ho;Sohn, Young-Soo
    • Journal of Sensor Science and Technology
    • /
    • v.19 no.2
    • /
    • pp.142-148
    • /
    • 2010
  • We have compared and investigated the detection capabilities of antibody of immunoglobulin G(anti-IgG) immobilized by protein G and N-hydroxysuccinimide(NHS) at the end of the self-assembled monolayer(SAM). Surface plasmon resonance(SPR) sensor has been utilized to measure the interaction between biomolecules. After formation of the protein G and SAM, anti-IgG, bovine serum albumin(BSA) and IgG has been sequently injected. Through the reponse of the SPR, we can conclude that the protein G immobilized anti-IgG better than the SAM. In addition, IgG detection capability of the anti-IgG immobilized by the protein G showed better performance compared with that immobilized by the SAM.

A new purification method for the Fab and F(ab)2 fragment of 145-2C11, hamster anti-mouse CD3ε antibody

  • Kwack, Kyu-Bum
    • BMB Reports
    • /
    • v.33 no.2
    • /
    • pp.188-192
    • /
    • 2000
  • Recombinant protein G has been utilized in the purification of antibodies from various mammalian species based on the interaction of antibodies with protein G. The interaction between immunoglobulin and protein G may not be restricted to the Fc protion of antibodies, as many different $F(ab)_2$ or Fab fragments can also bind to protein G. I found both FAb $F(ab)_2$ of 145-2C11, a hamster anti-mouse $CD3{\varepsilon}$ antibody, bound to the protein G-sepharose. Interestingly, Fab and $F(ab)_2$ of 145-2C11 did not bind to the protein A-sepharose. The binding of Fab and $F(ab)_2$ of 145-2C11 to protein G provided a useful method to remove proteases, chopped fragments of the Fc region, and other contaminating proteins. The remaining intact antibody in the protease reaction mixture can be removed by using a protein A-sepharose, because the Fab and $F(ab)_2$ portions of 145-2C11 did not bind to protein A-sepharose. The specific binding of Fab and $F(ab)_2$ portions of 145-sC11 to a protein G-sepharose (though not to a protein A-sepharose) and binding of intact 145-2C11 to both protein A- and G-sepharose will be useful in developing an effective purification protocol for Fab and $F(ab)_2$ portions of 145-2C11.

  • PDF

Heterotrimeric G protein signaling and RGSs in Aspergillus nidulans

  • Yu Jae-Hyuk
    • Journal of Microbiology
    • /
    • v.44 no.2
    • /
    • pp.145-154
    • /
    • 2006
  • Heterotrimeric G proteins (G proteins) are conserved in all eukaryotes and are crucial components sensing and relaying external cues into the cells to elicit appropriate physiological and biochemical responses. Basic units of the heterotrimeric G protein signaling system include a G protein-coupled receptor (GPCR), a G protein composed of ${\alpha},\;{\beta},\;and\;{\gamma}$ subunits, and variety of effectors. Sequential sensitization and activation of these G protein elements translates external signals into gene expression changes, resulting in appropriate cellular behaviors. Regulators of G protein signaling (RGSs) constitute a crucial element of appropriate control of the intensity and duration of G protein signaling. For the past decade, G protein signaling and its regulation have been intensively studied in a number of model and/or pathogenic fungi and outcomes of the studies provided better understanding on the upstream regulation of vegetative growth, mating, development, virulence/pathogenicity establishment, and biosynthesis of secondary metabolites in fungi. This review focuses on the characteristics of the basic upstream G protein components and RGS proteins, and their roles controlling various aspects of biological processes in the model filamentous ascomycete fungus Aspergillus nidulans. In particular, their functions in controlling hyphal proliferation, asexual spore formation, sexual fruiting, and the mycotoxin sterigmatocystin production are discussed.

Effect of Daily Protein Allowances during Lay on Egg Production and Feed Cost of Broiler Breeders (육용종계 산란기의 단백질 공급수준이 산란능력과 경제성에 미치는 영향)

  • 함영훈;김상인;이규호
    • Korean Journal of Poultry Science
    • /
    • v.30 no.2
    • /
    • pp.101-106
    • /
    • 2003
  • In order to study the optimum daily protein allowance for broiler breeders of 24 to 64 weeks of age on a control-fed basis, an experiment was carried out with 400 hens of Arbor Acres strain. Four levels of protein allowances were used to supply 18 to 24g of protein per day in 2g increments. As the age of hens increased, a same stepwise increase and decrease in daily energy allotment was used in all treatments. Same amount of calcium, phosphorus, methionine and lysine were supplied in all treatments and throughout laying period. Hen-day egg production was highest in hens receiving 20g protein per day(p<0.05), but there was no significant difference among those fed daily protein ranging 18 to 22g, and increasing the daily protein allotment up to 24g resulted in a significant decrease(p<0.05). Average egg weight showed a trend to increase as the daily protein allowance increase(p<0.05), but no significant difference was found among the hens fed daily protein 20 to 24g. Feed and ME conversion was superior in hens receiving 20g daily protein(p<0.05). CP conversion was increased as the daily protein allowance increase(p<0.05), but there was no significant difference between hens receiving 18 and 20g daily protein. Feed cost required per egg or per kg egg was lowest in hens fed 20g daily protein. It could be concluded that the optimum daily protein allowance was 20g in all performances.

Can Moringa oleifera Be Used as a Protein Supplement for Ruminants?

  • Kakengi, A.M.V.;Shem, M.N.;Sarwatt, S.V.;Fujihara, T.
    • Asian-Australasian Journal of Animal Sciences
    • /
    • v.18 no.1
    • /
    • pp.42-47
    • /
    • 2005
  • The possibility of using Moringa oleifera as a ruminant protein supplement was investigated by comparison between nutritive and anti-nutritive value of its different morphological parts with that of conventionally used Leucaena leucocephala leaf meal (LL). Parameters determined were chemical composition, rumen degradable protein (RDP), acid detergent insoluble protein (ADIP), pepsin soluble protein (PESP), non-protein nitrogen (NPN) total soluble protein (TSP) and protein potentially digested in the intestine (PDI). Total phenols (TP) and total extractable tannins (TET) were also evaluated as anti-nutritive factors. In vitro gas production characteristics were measured and organic matter digestibility (OMD) was estimated basing on 24 h-gas production. Crude protein content ranged from 265-308 g/kg DM in M. oleifera leaves (MOL) and seed cake (MOC) respectively. Leucaena leucocephala and Moringa oleifera soft twigs and leaves (MOLSTL) had CP content of 236 and 195 g/kg DM while Moringa oleifera soft twigs alone (MOST) and Moringa oleifera bucks (MOB) had 160, 114 and 69.3 g/kg DM respectively. RDP was highest in (MOC) (181 g/kg DM) followed by (MOL) (177 g/kg DM) and was lowest in MOB (40 g/kg DM). The proportion of the protein that was not available to the animal (ADIP) was (p<0.05) higher in MOL and MOC (72 and 73 g/kg DM) respectively and lowest in LL (29 g/kg DM). The PDI was high in LL (74 g/kg DM) followed by MOC (55 g/kg DM) then MOL (16 g/kg DM). PESP was highest (p<0.05) in MOC followed by MOL then LL (273, 200 and 163 g/kg DM respectively). MOC exhibited highest NPN content (116 g/kg DM) and was lowest in MOB (18 g/kg DM) (p<0.05). Highly (p<0.05) TSP was observed in MOC and MOL (308 and 265 g/kg DM respectively) followed by LL (236 g/kg DM). MOL had negligible TET (20 g/kg DM) when compared with about 70 g/kg DM in LL. Highly (p<0.05) b and a+b values were observed for MOLSTL (602 and 691 g/kg DM respectively) followed by MOL (490 and 538 g/kg DM). Highest c value was observed in MOSTL followed by MOC and MOL (0.064, 0.056 and 0.053 rate/hour) respectively. OMD was highest (p<0.05) for MOSTL followed by MOC and then MOL (579, 579 and 562 g/kg DM respectively). LL exhibited lower (p<0.05) OMD (467 g/kg DM). It was concluded from this study that the high crude protein content in MOL and MOLST could be well utilized by ruminant animals and increase animal performance however, high proportion of unavailable protein to the lower gut of animals and high rumen degradable protein due to negligible tannin content render it a relatively poor protein supplement for ruminants. MOC can be a best alternative protein supplement to leaves and leaves and soft twigs for ruminants.

Arabidopsis nucleoside diphosphate kinase-2 as a plant GTPase activating protein

  • Shen, Yu;Han, Yun-Jeong;Kim, Jeong-Il;Song, Pill-Soon
    • BMB Reports
    • /
    • v.41 no.9
    • /
    • pp.645-650
    • /
    • 2008
  • Nucleoside diphosphate kinase (NDPK) is involved in multiple signaling pathways in mammalian systems, including G-protein signaling. Arabidopsis NDPK2, like its mammalian counterparts, is multifunctional despite its initial discovery phytochrome-interacting protein. This similarity raises the possibility that NDPK2 may play a role in G-protein signaling in plants. In the present study, we explore the potential relationship between NDPK2 and the small G proteins, Pra2 and Pra3, as well as the heterotrimeric G protein, GPA1. We report a physical interaction between NDPK2 and these small G proteins, and demonstrate that NDPK2 can stimulate their GTPase activities. Our results suggest that NDPK2 acts as a GTPase-activating protein for small G proteins in plants. We propose that NDPK2 might be a missing link between the phytochrome-mediated light signaling and G protein-mediated signaling.

Modeling Nutrient Supply to Ruminants: Frost-damaged Wheat vs. Normal Wheat

  • Yu, Peiqiang;Racz, V.
    • Asian-Australasian Journal of Animal Sciences
    • /
    • v.23 no.3
    • /
    • pp.333-339
    • /
    • 2010
  • The objectives of this study were to use the NRC-2001 model and DVE/OEB system to model potential nutrient supply to ruminants and to compare frost damaged (also called "frozen" wheat with normal wheat. Quantitative predictions were made in terms of: i) Truly absorbed rumen synthesized microbial protein in the small intestine; ii) Truly absorbed rumen undegraded feed protein in the small intestine; iii) Endogenous protein in the digestive tract; iv). Total truly absorbed protein in the small intestine; and v). Protein degraded balance. The overall yield losses of the frozen wheat were 24%. Results showed that using the DVE/OEB system to predict the potential nutrient supply, the frozen wheat had similar truly absorbed rumen synthesized microbial protein (65 vs. 66 g/kg DM; p>0.05), tended to have lower truly absorbed rumen undegraded feed protein (39 vs. 53 g/kg DM; p<0.10) and had higher endogenous protein (14 vs. 9 g/kg DM; p<0.05). Total truly absorbed protein in the small intestine was significantly lower (89 vs. 110 g/kg DM, p<0.05) in the frozen wheat. The protein degraded balance was similar and both were negative (-2 vs. -1 g/kg DM). Using the NRC-2001 model to predict the potential nutrient supply, the frozen wheat also had similar truly absorbed rumen synthesized microbial protein (average 56 g/kg DM; p>0.05), tended to have lower truly absorbed rumen undegraded feed protein (35 vs. 48, g/kg DM; p<0.10) and had similar endogenous protein (average 4 g/kg DM; p>0.05). Total truly absorbed protein in the small intestine was significantly lower (95 vs. 108 g/kg DM, p<0.05) in the frozen wheat. The protein degraded balance was not significantly different and both were negative (-16 vs. -19 g/kg DM). In conclusion, both models predict lower protein value and negative protein degraded balance in the frozen wheat. The frost damage to the wheat reduced nutrient content and availability and thus reduced nutrient supply to ruminants by around 12 to 19%.

Immunoassay of haptoglobin and transferrin with proteinG-containing QCM sensor chip and unpurified antiserum (Protein G를 포함하는 수정미소저울 센서 칩과 정제되지 않은 항혈청을 이용한 헵토글로빈과 트랜스페린의 면역분석)

  • Ha, In-Young;Choi, Suk-Jung
    • Journal of Sensor Science and Technology
    • /
    • v.17 no.5
    • /
    • pp.380-386
    • /
    • 2008
  • Quartz crystal microbalance immunosensor has a capacity to perform a label-free and real time detection of a trace amount of analyte through the specific interaction between antibody and antigen. However, immobilization of antibody molecules on the sensor surface is a troublesome procedure for researchers who are not experienced in chemistry. Protein G has a specific affinity to antibody and would serve as a capturing agent for antibody when immobilized on the sensor surface. In this work, we prepared a protein G sensor chip by immobilizing protein G on the surface of quartz crystal microbalance and examined its capability to detect human haptoglobin or human transferrin with unpurified corresponding antiserum. Specific and dose dependent response was observed when the protein G chip was used for detection of antigens after saturated with antiserum. We also verified several advantageous aspects of the protein G chip such as improved flexibility and sensitivity.