• 제목/요약/키워드: Gist

검색결과 815건 처리시간 0.033초

Structural Insights into Porphyrin Recognition by the Human ATP-Binding Cassette Transporter ABCB6

  • Kim, Songwon;Lee, Sang Soo;Park, Jun Gyou;Kim, Ji Won;Ju, Seulgi;Choi, Seung Hun;Kim, Subin;Kim, Na Jin;Hong, Semi;Kang, Jin Young;Jin, Mi Sun
    • Molecules and Cells
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    • 제45권8호
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    • pp.575-587
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    • 2022

  • Human ABCB6 is an ATP-binding cassette transporter that regulates heme biosynthesis by translocating various porphyrins from the cytoplasm into the mitochondria. Here we report the cryo-electron microscopy (cryo-EM) structures of human ABCB6 with its substrates, coproporphyrin III (CPIII) and hemin, at 3.5 and 3.7 Å resolution, respectively. Metal-free porphyrin CPIII binds to ABCB6 within the central cavity, where its propionic acids form hydrogen bonds with the highly conserved Y550. The resulting structure has an overall fold similar to the inward-facing apo structure, but the two nucleotide-binding domains (NBDs) are slightly closer to each other. In contrast, when ABCB6 binds a metal-centered porphyrin hemin in complex with two glutathione molecules (1 hemin: 2 glutathione), the two NBDs end up much closer together, aligning them to bind and hydrolyze ATP more efficiently. In our structures, a glycine-rich and highly flexible "bulge" loop on TM helix 7 undergoes significant conformational changes associated with substrate binding. Our findings suggest that ABCB6 utilizes at least two distinct mechanisms to fine-tune substrate specificity and transport efficiency.

  • https://doi.org/10.14348/molcells.2022.0040 인용 PDF KSCI

하부식도에서 발생한 GIST 1예 (Esophageal GIST : case report)

  • 이상훈;오창권;이기석;조영업;김경래
    • 대한기관식도과학회지
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    • 제9권1호
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    • pp.87-91
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    • 2003

  • Currently gastrointestinal mesenchymal tumors are divided into three major categories: myogenic tumors(leiomyoma, leiomyosarcoma), neurogenic tumors (schwannomas) and neoplasms that belong to neither group, which are known by GIST(gastrointestinal stromal tumors). The stromal tumors are hetrogenous, so that they may show myogenic or neurogenic differentiation or both, or no differentiation at all in some patients. The best defining feature for GIST is their expression of KIT-protein(CD117). Leiomyomas are the most common mesenchymal tumor in esophagus. Esophageal GISTS are very rare in comparision to those of the stomach and intestine. Recently we experieneced one case of the esophageal GIST, so that we describe an esophageal GIST on immunohistochemical analysis. A 70 years old woman complained of dysphagia and nausea for 3 days. FGS showed a huge elevated lesion in lower esophagus 33cm distal to incisor, which was covered with normal mucosa. CT and UGI showed the intramural tumor of lower third of the esophagus. The distal esophagectomy and esophago-gastrostomy were performed. The tumor was located in lower third of esophagus and measured as $6{\times}3.7$cm in size. Immunohistochemically, it showed weakly positive CD117 and diffusely positive S-100. SMA, desmin, NES and chromogranin showed negative immune-reaction. The patient was followed for 15 month after operation. There was no recurrence.

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아동의 축어 기억과 요점 기억의 발달과 과제의 영향에 관한 연구 (The Development of Verbatim and Gist Memory: Task Effects)

  • 송하나;최경숙
    • 아동학회지
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    • 제18권2호
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    • pp.283-297
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    • 1997

  • This study examined the development of verbatim and gist memory, and the effects of the relevance and inferential direction of the task on the development of the verbatim and gist memory. The subjects were second, fourth and sixth grade children in elementary schools. Each age group consisted of forty children. Eight sets of inference tasks were administered to each subject. In the task, the relevent and the extraneous sentences were mixed for inferential direction. The sentences that described 'which term is more' were inserted in half of the task and the sentences that indicated the direct numbers were included in the other half of the task. The task was presented by the audio tape in which instruction was recorded by one speaker. Results showed that (1) age differences in verbatim memory were significant but age differences in gist memory were not significant. These results indicate that the processes of verbatim and gist memory are separate and independent. (2) The relevance and inferential direction of the task affect gist memory but no verbatim memory. This result also supported independence between verbatim and gist memory. It was suggested that these results can be interpreted in terms of fuzzy trace theory.

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