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Volume 97, Issue 12
Displaying 1-6 of 6 articles from this issue
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[in Japanese]2023 Volume 97 Issue 12 Pages 527-539
Published: December 25, 2023
Released on J-STAGE: December 31, 2024
JOURNAL OPEN ACCESSDownload PDF (1532K) -
Hideaki Tsuge2023 Volume 97 Issue 12 Pages 540-551
Published: December 25, 2023
Released on J-STAGE: December 31, 2024
JOURNAL OPEN ACCESSADP-ribosylation is a reversible post-translational modification defined by adding ADP-ribose moieties from NAD + to the target. As bacterial toxins, cholera toxin ADP-ribosylates a specific arginine in the Gsα of heteromeric G-proteins, and diphtheria toxin ADP-ribosylates the eukaryotic elongation factor 2 (eEF2). Later, the ADP-ribosylating enzymes in cholera toxin and diphtheria toxin were named ARTC family and ARTD family, respectively, because there is each specific motives characterized ADP-ribosylating enzymes in cholera toxin and diphtheria toxin. We have studied functional studies based on the ARTC crystal structures. We especially revealed the complex structure of Ia-actin and C3-RhoA and the critical recognition mechanism of Arg and Asn ADP-ribosylation. Next, we revealed the ScARP structure, which participates in ADP-ribosylation from GDP. From these studies, we have concluded that although there are various substrates for ADP-ribosylating enzymes, there is a common substrate recognition mechanism regardless of protein and DNA for ADP-ribosylation. In addition, we have studied the protein translocation mechanism in binary toxins, such as C.perfringens iota toxin and C.difficile CDT. Using cryo-EM, we have revealed the binary toxin complex structure and the first unfolding structure of Ia and CDTa in these pore complexes.View full abstractDownload PDF (1947K) -
Kiyoshi Tanaka, Misora Ao, Fumihiko Horio2023 Volume 97 Issue 12 Pages 552-557
Published: December 25, 2023
Released on J-STAGE: December 31, 2024
JOURNAL OPEN ACCESSMany papers have been published on the relationship between vitamin C (VC) and disease risk. However, marked discrepancy exists in the relationship between VC and disease between the observational and intervention studies and the relationship is mostly positive in the former and negative in the latter. In this review article, we make a consideration underlying such discrepancy between VC and cardiovascular disease (CVD) risk.
Cohort and nested case-control studies have almost unequivocally shown that higher VC intake or higher plasma VC concentration is associated with decreased risk of various diseases including CVD. Of note, CVD risk exhibits a linear relationship with plasma VC level, while it exhibits a non-linear relationship with VC intake, which can be explained by the VC’s kinetic characteristics. Since intestinal absorption and renal tubular reabsorption of VC are tightly regulated, plasma VC concentration reaches a plateau with the increased VC intake.
In contrast, the negative results have been reported mostly in the intervention studies including the largest scale one, Physicians’ Health Study Ⅱ, in which more than 7,000 subjects in each group of the placebo and intervention were followed for 8 years. Such results could be explained by the following reasons: most participants are VC-sufficient and vitamin intervention is effective in the deficient subjects, but not in sufficient ones.View full abstractDownload PDF (1344K) -
Akari Nakamura, Koji Fukui2023 Volume 97 Issue 12 Pages 558-560
Published: December 25, 2023
Released on J-STAGE: December 31, 2024
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Ayami Sato, Akihito Ishigami2023 Volume 97 Issue 12 Pages 561-563
Published: December 25, 2023
Released on J-STAGE: December 31, 2024
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2023 Volume 97 Issue 12 Pages 564-569
Published: 2023
Released on J-STAGE: December 31, 2024
JOURNAL OPEN ACCESSDownload PDF (763K)
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