The Experts below are selected from a list of 21 Experts worldwide ranked by ideXlab platform
Martha M. Howe - One of the best experts on this subject based on the ideXlab platform.
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Bacteriophage Mu Mor protein requires ??70 to activate the Mu middle promoter
Journal of Bacteriology, 1993Co-Authors: Kalai Mathee, Martha M. HoweAbstract:Transcription during the bacteriophage Mu lytic cycle occurs in three phases: early, middle, and late. Middle transcription requires the early gene product Mor for its activation. Mor protein overproduction was accomplished by fusing the mor gene to an efficient phage T7 promoter and translation initiation region. A protein fraction highly enriched for Escherichia coli RNA polymerase (E sigma 70) from the Mor-overproducing strain was able to activate transcription from both the tac promoter (Ptac) and the Mu middle promoter (Pm) in vitro. Transcription initiation from Pm was Mor dependent, and the RNA 5' end was identical to that of in vivo RNA. Addition of anti-sigma 70 antibody to transcription reactions containing Ptac and Pm resulted in inhibition of transcription from both promoters; addition of purified sigma 70 restored transcription. These results indicate that Mor-dependent activation requires sigma 70 and therefore imply that Mor is not an alternate sigma factor. This conclusion was further substantiated by a Reconstitution Experiment with purified proteins in which all three components, Mor, sigma 70, and core RNA polymerase, were required for Pm-dependent transcription in vitro. The sigma 70 dependence of Mor-specific transcription and the amino acid sequence similarity between Mor and C (an activator for Mu late transcription) both support the hypothesis that Mor functions mechanistically as an activator protein.
Kalai Mathee - One of the best experts on this subject based on the ideXlab platform.
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Bacteriophage Mu Mor protein requires ??70 to activate the Mu middle promoter
Journal of Bacteriology, 1993Co-Authors: Kalai Mathee, Martha M. HoweAbstract:Transcription during the bacteriophage Mu lytic cycle occurs in three phases: early, middle, and late. Middle transcription requires the early gene product Mor for its activation. Mor protein overproduction was accomplished by fusing the mor gene to an efficient phage T7 promoter and translation initiation region. A protein fraction highly enriched for Escherichia coli RNA polymerase (E sigma 70) from the Mor-overproducing strain was able to activate transcription from both the tac promoter (Ptac) and the Mu middle promoter (Pm) in vitro. Transcription initiation from Pm was Mor dependent, and the RNA 5' end was identical to that of in vivo RNA. Addition of anti-sigma 70 antibody to transcription reactions containing Ptac and Pm resulted in inhibition of transcription from both promoters; addition of purified sigma 70 restored transcription. These results indicate that Mor-dependent activation requires sigma 70 and therefore imply that Mor is not an alternate sigma factor. This conclusion was further substantiated by a Reconstitution Experiment with purified proteins in which all three components, Mor, sigma 70, and core RNA polymerase, were required for Pm-dependent transcription in vitro. The sigma 70 dependence of Mor-specific transcription and the amino acid sequence similarity between Mor and C (an activator for Mu late transcription) both support the hypothesis that Mor functions mechanistically as an activator protein.
Honda K - One of the best experts on this subject based on the ideXlab platform.
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Specificity of lipoamide dehydrogenase for alpha-keto acid dehydrogenase complexes and the glycine cleavage system.
Fukushima journal of medical science, 1990Co-Authors: Hakozaki M, Honda KAbstract:Rat liver lipoamide dehydrogenase (LipDH) was separated into three types on DE-32 column chromatography, but no difference was observed among them in either immunological reactivity or enzymatic properties. A Reconstitution Experiment of branched-chain alpha-keto acid dehydrogenase complex (BCKADH) revealed that the most anionic type of LipDH was the most effective for the enzyme complex while the three types of LipDH were the same in the affinity for BCKADH subcomplex. All three types of LipDH were equally effective in reconstituting pyruvate dehydrogenase complex, alpha-ketoglutarate dehydrogenase complex and the glycine cleavage system. However, either pyruvate dehydrogenase or alpha-keto-glutarate dehydrogenase complex appeared to involve a certain LipDH in vivo which was firmly integrated into and hardly dissociable from the complex. A broad specificity of LipDH was observed for the glycine cleavage system. When BCKADH Reconstitution Experiments were carried out with both LipDHs from various sources and purified rat liver BCKADH subcomplex, the effectiveness of animal LipDHs was proportional to the extent of their immunological reactivity to the anti-rat LipDH antibody. However, BCKADH activity was also restored by a certain bacterial LipDH which had no cross-reactivity with the antibody, and LipDHs from some bacterial species, which reacted well with the antibody, showed no effect for the Reconstitution of BCKADH. Thus, the determinant(s) of LipDH for the integration into alpha-keto acid dehydrogenase complexes including BCKADH can be its tertiary and/or quarternary structure rather than its primary and secondary structures.
Naomasa Miki - One of the best experts on this subject based on the ideXlab platform.
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Purification and Characterization of Three MEKA-Like Proteins in Liver: Association of a 94 kDa Protein with β γ Subunits of G-Proteins
Biochemical and Biophysical Research Communications, 1993Co-Authors: Eiichi Taira, Natsuki Takaha, Hitoshi Sohma, Toyoaki Akino, Yoshitaka Fukada, K. Sanada, Naomasa MikiAbstract:Abstract Retinal 32 kDa MEKA protein (rMEKA) exists in the photoreceptor cells and forms a complex with β γ subunit of transducin. Bovine liver contained three MEKA-like proteins (94 kDa, 35 kDa-a, 35 kDa-b) which reacted with a rMEKA antibody. Each protein was purified as a single band on a SDS-PAGE and used for a Reconstitution Experiment with α and β γ subunits of cerebral G-proteins (Go/i). The 94 kDa protein inhibited GTP-binding ability of Gα by forming a complex with β γ subunit.
Jeng Im - One of the best experts on this subject based on the ideXlab platform.
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Irreversible inactivation of diacylglycerol kinase-II requires a mediator.
Biochemistry international, 1991Co-Authors: Chen Q, Klemm N, Jeng ImAbstract:Cytosolic diacylglycerol kinase was irreversibly inactivated by 5'-AMP since the enzyme remained less active after the removal of 5'-AMP by P-10 gel chromatography. The inactivation was time-dependent, suggesting the involvement of a covalent bond modification. A Reconstitution Experiment detected a rat brain cytosolic mediator for the effect of 5'-AMP. A protein kinase rich fraction prepared from rat liver was also capable of restoring the sensitivity of diacylglycerol kinase-II to 5'-AMP. We propose that 5'-AMP-activated protein kinase is the mediator which inactivates diacylglycerol kinase-II, possibly by phosphorylation.