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Structural Insights into Porphyrin Recognition by the Human ATP-Binding Cassette Transporter ABCB6
Songwon Kim,이상수,박준규,김지원,Seulgi Ju,Seung Hun Choi,김수빈,Na Jin Kim,Semi Hong,강진영,Mi Sun Jin 한국분자세포생물학회 2022 Molecules and cells Vol.45 No.8
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. Metalfree 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.
Radiation-related occupational cancer and its recognition criteria in South Korea
Songwon Seo,Dalnim Lee,Ki Moon Seong,Sunhoo Park,Soo-Geun Kim,Jong-Uk Won,Young Woo Jin 대한직업환경의학회 2018 대한직업환경의학회지 Vol.30 No.-
Ionizing radiation is a well-known carcinogen, and is listed as one carcinogenic agent of occupational cancer. Given the increase in the number of workers exposed to radiation, as well as the increase in concern regarding occupational cancer, the number of radiation-related occupational cancer claims is expected to increase. Unlike exposure assessment of other carcinogenic agents in the workplace, such as asbestos and benzene, radiation exposure is usually assessed on an individual basis with personal dosimeters, which makes it feasible to assess whether a worker’s cancer occurrence is associated with their individual exposure. However, given the absence of a threshold dose for cancer initiation, it remains difficult to identify radiation exposure as the root cause of occupational cancer. Moreover, the association between cancer and radiation exposure in the workplace has not been clearly established due to a lack of scientific evidence. Therefore, criteria for the recognition of radiation-related occupational cancer should be carefully reviewed and updated with new scientific evidence and social consensus. The current criteria in Korea are valid in terms of eligible radiogenic cancer sites, adequate latent period, assessment of radiation exposure, and probability of causation. However, reducing uncertainty with respect to the determination of causation between exposure and cancer and developing more specific criteria that considers mixed exposure to radiation and other carcinogenic agents remains an important open question.
Radiation-related occupational cancer and its recognition criteria in South Korea
Seo, Songwon,Lee, Dalnim,Seong, Ki Moon,Park, Sunhoo,Kim, Soo-Geun,Won, Jong-Uk,Jin, Young Woo BioMed Central 2018 Annals of occupational and environmental medicine Vol.30 No.1
<P>Ionizing radiation is a well-known carcinogen, and is listed as one carcinogenic agent of occupational cancer. Given the increase in the number of workers exposed to radiation, as well as the increase in concern regarding occupational cancer, the number of radiation-related occupational cancer claims is expected to increase. Unlike exposure assessment of other carcinogenic agents in the workplace, such as asbestos and benzene, radiation exposure is usually assessed on an individual basis with personal dosimeters, which makes it feasible to assess whether a worker’s cancer occurrence is associated with their individual exposure. However, given the absence of a threshold dose for cancer initiation, it remains difficult to identify radiation exposure as the root cause of occupational cancer. Moreover, the association between cancer and radiation exposure in the workplace has not been clearly established due to a lack of scientific evidence. Therefore, criteria for the recognition of radiation-related occupational cancer should be carefully reviewed and updated with new scientific evidence and social consensus. The current criteria in Korea are valid in terms of eligible radiogenic cancer sites, adequate latent period, assessment of radiation exposure, and probability of causation. However, reducing uncertainty with respect to the determination of causation between exposure and cancer and developing more specific criteria that considers mixed exposure to radiation and other carcinogenic agents remains an important open question.</P>
SPH에서 임의 형상의 강체면에 대한 탄소성 접촉 해석
서송원(Songwon Seo),이재훈(Jaehoon Lee),민옥기(Oakkey Min) 대한기계학회 2004 대한기계학회 춘추학술대회 Vol.2004 No.4
There is few research about contact problem for a rigid surface with an arbitrary shape in SPH. The variational equation based on the virtual work principle is derived and its solution is obtained by the penalty method. It is proposed a new method that can determine the parameters for a penetration and a penetration rate used in the penalty method. The reproducing condition is adopted to correct the deficiency of kernel on the boundary. In order to calculate a penetration of particles, after checking boundary particles for deformable body boundary normal vectors were determined on the rigid surface. Numerical simulations for models which have rigid surface with an arbitrary shape were conducted to validate the proposed method in 2D. The results of those analysis represent that the contact algorithm proposed in this study works properly.
Park, SongWon,Lim, Seong-Woo The Society of Korean Medicine 2019 대한한의학회지 Vol.40 No.4
Objectives: The purpose of this meta-analysis was to evaluate the effects of Yukgunja-tang(YGJT, Rikkunshito, Liujunzi) on Gastroesophageal Reflux Disease(GERD). Methods: Sixteen electronic databases were used to search for studies published through March 2019, and a randomized controlled study was conducted to study the effects of YGJT or modified YGJT on GERD. Study quality was assessed using the risk bias tool provided by Cochran, and data analysis was performed using Review Manager 5.3.0 software Results: Two-hundred and forty articles were initially searched, and 13 studies that satisfied the study criteria were evaluated qualitatively; 11 of the 13 were included in the meta-analysis. In the two studies, the effects of YGJT and a placebo were compared. Meta-analysis showed that YGJT significantly improved FSSG (Frequency Scale for the Symptoms of GERD) scores, but not GSRS (Gastrointestinal Symptom Rating Scale) scores (FSSG: MD -2.40, 95% CI [-5.31, 0.51], p=0.11, GSRS: MD 0.05, 95% CI [-0.12, 0.22], p=0.55). Meta-analysis of nine studies comparing the efficacies of YGJT and conventional medicine showed that YGJT had a significant clinical effect (OR 5.72; 95% CI [3.41, 9.61]; I2 p<0.00001). Conclusion: This study suggests that YGJT effectively relieves the symptoms of GERD. Unfortunately, owing to the small sample sizes, limitations of several methodological qualities, we believe large-scale clinical studies with less bias will provide evidence of qualitative improvement.
서송원(Songwon Seo),민옥기(Oakkey Min) 대한기계학회 2002 대한기계학회 춘추학술대회 Vol.2002 No.9
SPH is an appealing and valuable computational tool using no background mesh, especially for high deformation events such as impact. But, although research has widely done since invented in 1977, this method still have several problems-lacking consistency, tensile instability and especially boundary condition treatment. This paper review current works for the method of imposing boundary conditions and test several model to certify a validity of its methods. It is compared a method using a ghost particle with that using a boundary condition about a symmetric model. Numerical tests are shown a reasonable result when impose a traction or velocity constraint to the models by equations of boundary constraint condition.