ABSTRACT
p97 processes ubiquitinated substrates and plays a central role in cellular protein homeostasis. Here, we report a series of cryo-EM structures of the substrate-engaged human p97 complex with resolutions ranging from 2.9 to 3.8 Å that captured 'power-stroke'-like motions of both the D1 and D2 ATPase rings of p97. A key feature of these structures is the critical conformational changes of the intersubunit signaling (ISS) motifs, which tighten the binding of nucleotides and neighboring subunits and contribute to the spiral staircase conformation of the D1 and D2 rings. In addition, we determined the cryo-EM structure of human p97 in complex with NMS-873, a potent p97 inhibitor, at a resolution of 2.4 Å. The structures showed that NMS-873 binds at a cryptic groove in the D2 domain and interacts with the ISS motif, preventing its conformational change and thus blocking substrate translocation allosterically.
Subject(s)
Adenosine Triphosphate/chemistry , Protein Folding , Proteostasis/physiology , Signal Transduction/physiology , Valosin Containing Protein/metabolism , Acetanilides/pharmacology , Animals , Benzothiazoles/pharmacology , Cryoelectron Microscopy , Endoplasmic Reticulum/metabolism , Endoplasmic Reticulum-Associated Degradation/physiology , Humans , Intracellular Signaling Peptides and Proteins/metabolism , Nuclear Proteins/metabolism , Proteasome Endopeptidase Complex/metabolism , Protein Conformation , Ubiquitinated Proteins/metabolism , Valosin Containing Protein/antagonists & inhibitorsABSTRACT
BACKGROUND: During the COVID-19 epidemic period, Traditional Chinese Medicine (TCM) course for international students of Medical Bachelor, Bachelor of Surgery (MBBS) program in Zhejiang University has shifted from traditional classroom to online environment. This study aimed to investigate MBBS international students' perception on online TCM course, and to assess the online learning efficacy. METHODS: A total of 84 MBBS international students attending course of "Basic Traditional Chinese Medicine" during 2020 academic years at Zhejiang University were enrolled in this study. A quantitative questionnaire was respectively completed before and after the TCM course using a pretest-post-test design. By means of two online learning platforms, Learning in ZJU and DingTalk, TCM course was broadcast in both live and archived format to students. RESULTS: A total of 48 participants completed both baseline and follow-up questionnaires. The majority of participants preferred face-to-face classroom learning (26, 54.17% of total) when compared with online learning. Students felt that the course had brought in much benefits (mean 3.88, SD 0.87), and they were satisfied with the course content (mean 3.83, SD 0.95). Students' TCM related knowledge and their behaviors of discussion and consulting were significantly improved by online TCM course (all P < 0.001). Students' awareness of the necessity of TCM education and their feeling of difficulty in learning TCM were significantly strengthened (P = 0.042, 0.025, respectively). CONCLUSION: Online learning is a good alternative for TCM course of MBBS international students when classroom learning is suspended, whereas it cannot replace the need for onsite and face-to-face learning.